Change cthunk implementation + cm7 support
Change cthunk implementation + cm7 support

- Add support of cortex-M7 for cthunk.
- Change the cthunk trampoline implementation to safer and quicker
solutions:
 * thumb2, the behaviour was undefined. new implementation use now 2
instructions
 * thumb, The new implementation use 3 instructions instead of 6.

andreaslarssonublox/mbed,cvtsi2sd/mbed-os,maximmbed/mbed,maximmbed/mbed,monkiineko/mbed-os,maximmbed/mbed,kjbracey-arm/mbed,fanghuaqi/mbed,arostm/mbed-os,svastm/mbed,bcostm/mbed-os,nRFMesh/mbed-os,arostm/mbed-os,karsev/mbed-os,CalSol/mbed,HeadsUpDisplayInc/mbed,netzimme/mbed-os,karsev/mbed-os,svastm/mbed,Archcady/mbed-os,radhika-raghavendran/mbed-os5.1-onsemi,YarivCol/mbed-os,YarivCol/mbed-os,ryankurte/mbed-os,mazimkhan/mbed-os,theotherjimmy/mbed,andreaslarssonublox/mbed,bcostm/mbed-os,CalSol/mbed,radhika-raghavendran/mbed-os5.1-onsemi,theotherjimmy/mbed,karsev/mbed-os,YarivCol/mbed-os,maximmbed/mbed,kl-cruz/mbed-os,monkiineko/mbed-os,screamerbg/mbed,svastm/mbed,fahhem/mbed-os,RonEld/mbed,catiedev/mbed-os,mikaleppanen/mbed-os,karsev/mbed-os,HeadsUpDisplayInc/mbed,nvlsianpu/mbed,mmorenobarm/mbed-os,mmorenobarm/mbed-os,nRFMesh/mbed-os,andcor02/mbed-os,NXPmicro/mbed,netzimme/mbed-os,catiedev/mbed-os,mazimkhan/mbed-os,adustm/mbed,theotherjimmy/mbed,theotherjimmy/mbed,netzimme/mbed-os,cvtsi2sd/mbed-os,Archcady/mbed-os,svogl/mbed-os,adustm/mbed,nRFMesh/mbed-os,infinnovation/mbed-os,pradeep-gr/mbed-os5-onsemi,adustm/mbed,mazimkhan/mbed-os,bulislaw/mbed-os,ryankurte/mbed-os,bulislaw/mbed-os,screamerbg/mbed,kjbracey-arm/mbed,c1728p9/mbed-os,radhika-raghavendran/mbed-os5.1-onsemi,RonEld/mbed,HeadsUpDisplayInc/mbed,betzw/mbed-os,j-greffe/mbed-os,CalSol/mbed,nvlsianpu/mbed,nRFMesh/mbed-os,arostm/mbed-os,pradeep-gr/mbed-os5-onsemi,bulislaw/mbed-os,screamerbg/mbed,infinnovation/mbed-os,mikaleppanen/mbed-os,HeadsUpDisplayInc/mbed,mbedmicro/mbed,HeadsUpDisplayInc/mbed,fahhem/mbed-os,adamgreen/mbed,catiedev/mbed-os,andreaslarssonublox/mbed,arostm/mbed-os,c1728p9/mbed-os,svogl/mbed-os,mbedmicro/mbed,arostm/mbed-os,ryankurte/mbed-os,andcor02/mbed-os,infinnovation/mbed-os,betzw/mbed-os,infinnovation/mbed-os,radhika-raghavendran/mbed-os5.1-onsemi,ryankurte/mbed-os,monkiineko/mbed-os,nRFMesh/mbed-os,screamerbg/mbed,ryankurte/mbed-os,andcor02/mbed-os,nRFMesh/mbed-os,theotherjimmy/mbed,fahhem/mbed-os,kl-cruz/mbed-os,fanghuaqi/mbed,screamerbg/mbed,netzimme/mbed-os,j-greffe/mbed-os,c1728p9/mbed-os,NXPmicro/mbed,pradeep-gr/mbed-os5-onsemi,netzimme/mbed-os,RonEld/mbed,j-greffe/mbed-os,infinnovation/mbed-os,kl-cruz/mbed-os,fanghuaqi/mbed,fahhem/mbed-os,theotherjimmy/mbed,karsev/mbed-os,HeadsUpDisplayInc/mbed,pradeep-gr/mbed-os5-onsemi,adamgreen/mbed,betzw/mbed-os,adustm/mbed,cvtsi2sd/mbed-os,andreaslarssonublox/mbed,svogl/mbed-os,fahhem/mbed-os,arostm/mbed-os,andcor02/mbed-os,bcostm/mbed-os,nvlsianpu/mbed,mmorenobarm/mbed-os,pradeep-gr/mbed-os5-onsemi,radhika-raghavendran/mbed-os5.1-onsemi,infinnovation/mbed-os,Archcady/mbed-os,nvlsianpu/mbed,adamgreen/mbed,adamgreen/mbed,j-greffe/mbed-os,c1728p9/mbed-os,mmorenobarm/mbed-os,mbedmicro/mbed,cvtsi2sd/mbed-os,c1728p9/mbed-os,svastm/mbed,RonEld/mbed,bcostm/mbed-os,betzw/mbed-os,YarivCol/mbed-os,svogl/mbed-os,adustm/mbed,cvtsi2sd/mbed-os,NXPmicro/mbed,mazimkhan/mbed-os,monkiineko/mbed-os,NXPmicro/mbed,pradeep-gr/mbed-os5-onsemi,bcostm/mbed-os,CalSol/mbed,screamerbg/mbed,mazimkhan/mbed-os,j-greffe/mbed-os,mikaleppanen/mbed-os,nvlsianpu/mbed,svastm/mbed,bulislaw/mbed-os,Archcady/mbed-os,j-greffe/mbed-os,kl-cruz/mbed-os,RonEld/mbed,mazimkhan/mbed-os,maximmbed/mbed,svogl/mbed-os,betzw/mbed-os,betzw/mbed-os,Archcady/mbed-os,andreaslarssonublox/mbed,netzimme/mbed-os,nvlsianpu/mbed,YarivCol/mbed-os,bcostm/mbed-os,bulislaw/mbed-os,c1728p9/mbed-os,kl-cruz/mbed-os,andcor02/mbed-os,radhika-raghavendran/mbed-os5.1-onsemi,kjbracey-arm/mbed,NXPmicro/mbed,fahhem/mbed-os,andcor02/mbed-os,mmorenobarm/mbed-os,cvtsi2sd/mbed-os,adamgreen/mbed,ryankurte/mbed-os,mikaleppanen/mbed-os,kl-cruz/mbed-os,catiedev/mbed-os,Archcady/mbed-os,mbedmicro/mbed,kjbracey-arm/mbed,monkiineko/mbed-os,CalSol/mbed,karsev/mbed-os,fanghuaqi/mbed,catiedev/mbed-os,NXPmicro/mbed,CalSol/mbed,svogl/mbed-os,monkiineko/mbed-os,RonEld/mbed,adamgreen/mbed,maximmbed/mbed,mikaleppanen/mbed-os,fanghuaqi/mbed,mbedmicro/mbed,bulislaw/mbed-os,YarivCol/mbed-os,adustm/mbed,catiedev/mbed-os,mikaleppanen/mbed-os,mmorenobarm/mbed-os