mraa.c: check already initialised before anything else in mraa_init
mraa.c: check already initialised before anything else in mraa_init

Signed-off-by: Brendan Le Foll <3e0e8c4069934e8b47d99704927a85c66c0ceb33@intel.com>

sergev/mraa,arunlee77/mraa,pctj101/mraa,zBMNForks/mraa,noahchense/mraa,neuroidss/mraa,seem-sky/mraa,g-vidal/mraa,seem-sky/mraa,Jon-ICS/mraa,seem-sky/mraa,andreivasiliu2211/mraa,alexandru-elisei/mraa,anonymouse64/mraa,SyrianSpock/mraa,anonymouse64/mraa,matt-auld/mraa,allela-roy/mraa,g-vidal/mraa,alexandru-elisei/mraa,Hbrinj/mraa,g-vidal/mraa,nioinnovation/mraa,STANAPO/mraa,ncrastanaren/mraa,matt-auld/mraa,alex1818/mraa,spitfire88/mraa,intel-iot-devkit/mraa,malikabhi05/mraa,allela-roy/mraa,neuberfran/mraa,malikabhi05/mraa,whbruce/mraa,yoyojacky/mraa,tripzero/mraa,zBMNForks/mraa,SyrianSpock/mraa,Propanu/mraa,malikabhi05/mraa,smileboywtu/mraa,alext-mkrs/mraa,damcclos/mraa,spitfire88/mraa,alexandru-elisei/mraa,ncrastanaren/mraa,andreivasiliu2211/mraa,arunlee77/mraa,zBMNForks/mraa,petreeftime/mraa,jontrulson/mraa,andreivasiliu2211/mraa,Propanu/mraa,mircea/mraa,yongli3/mraa,tripzero/mraa,stefan-andritoiu/mraa,SyrianSpock/mraa,mircea/mraa,KurtE/mraa,intel-iot-devkit/mraa,damcclos/mraa,anonymouse64/mraa,Pillar1989/mraa,stefan-andritoiu/mraa,andreivasiliu2211/mraa,seem-sky/mraa,pctj101/mraa,damcclos/mraa,whbruce/mraa,alext-mkrs/mraa,stefan-andritoiu/mraa,whbruce/mraa,Hbrinj/mraa,yongli3/mraa,Kiritoalex/mraa,Propanu/mraa,neuroidss/mraa,whbruce/mraa,neuroidss/mraa,matt-auld/mraa,ncrastanaren/mraa,alex1818/mraa,sergev/mraa,malikabhi05/mraa,ProfFan/mraa,stefan-andritoiu/mraa,stefan-andritoiu/mraa-gpio-chardev,intel-iot-devkit/mraa,yongli3/mraa,sundw2014/mraa,pctj101/mraa,neuberfran/mraa,sergev/mraa,yongli3/mraa,smileboywtu/mraa,Kiritoalex/mraa,STANAPO/mraa,Kiritoalex/mraa,pctj101/mraa,arfoll/mraa,w4ilun/mraa,mircea/mraa,alext-mkrs/mraa,arunlee77/mraa,KurtE/mraa,sundw2014/mraa,yoyojacky/mraa,w4ilun/mraa,sergev/mraa,stefan-andritoiu/mraa,timrtoo/Intel,petreeftime/mraa,Propanu/mraa,ncrastanaren/mraa,timrtoo/Intel,neuberfran/mraa,intel-iot-devkit/mraa,Jon-ICS/mraa,stefan-andritoiu/mraa-gpio-chardev,ProfFan/mraa,Propanu/mraa,arfoll/mraa,neuberfran/mraa,Pillar1989/mraa,alext-mkrs/mraa,Hbrinj/mraa,Meirtz/mraa,w4ilun/mraa,yoyojacky/mraa,spitfire88/mraa,stefan-andritoiu/mraa-gpio-chardev,KurtE/mraa,tripzero/mraa,alexandru-elisei/mraa,Meirtz/mraa,jontrulson/mraa,seem-sky/mraa,noahchense/mraa,spitfire88/mraa,timrtoo/Intel,w4ilun/mraa,g-vidal/mraa,ProfFan/mraa,jontrulson/mraa,jontrulson/mraa,KurtE/mraa,timrtoo/Intel,malikabhi05/mraa,neuberfran/mraa,jontrulson/mraa,Pillar1989/mraa,alext-mkrs/mraa,allela-roy/mraa,arfoll/mraa,sundw2014/mraa,sundw2014/mraa,Jon-ICS/mraa,stefan-andritoiu/mraa-gpio-chardev,noahchense/mraa,pctj101/mraa,ProfFan/mraa,nioinnovation/mraa,sundw2014/mraa,KurtE/mraa,alexandru-elisei/mraa,timrtoo/Intel,yongli3/mraa,smileboywtu/mraa,g-vidal/mraa,intel-iot-devkit/mraa,sergev/mraa,Meirtz/mraa,petreeftime/mraa,alex1818/mraa,nioinnovation/mraa,stefan-andritoiu/mraa-gpio-chardev,noahchense/mraa,Hbrinj/mraa,arfoll/mraa,arfoll/mraa,STANAPO/mraa,petreeftime/mraa,arunlee77/mraa,ncrastanaren/mraa,noahchense/mraa