dma: stm32f4x: Pull in sub-channel information from Kconfig
dma: stm32f4x: Pull in sub-channel information from Kconfig

The STM32 DMA controller supplies streams, which in turn provide a
selection of channels.  The stream number is provided by the DMA API
through it's 'channel' argument, but the sub-channel (within the
stream) is specified on an application case by case bases via Kconfig.

Change-Id: Ib5bfdb80f4d616516850787e1402164807771c5e
Signed-off-by: Lee Jones <630e34333487a351a857f6b705e04d30b37c1629@linaro.org>

aceofall/zephyr-iotos,nashif/zephyr,rsalveti/zephyr,sharronliu/zephyr,zephyrproject-rtos/zephyr,fbsder/zephyr,aceofall/zephyr-iotos,runchip/zephyr-cc3200,zephyriot/zephyr,explora26/zephyr,bboozzoo/zephyr,Vudentz/zephyr,finikorg/zephyr,rsalveti/zephyr,zephyrproject-rtos/zephyr,sharronliu/zephyr,nashif/zephyr,punitvara/zephyr,sharronliu/zephyr,pklazy/zephyr,runchip/zephyr-cc3200,mbolivar/zephyr,pklazy/zephyr,mbolivar/zephyr,mbolivar/zephyr,fbsder/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,sharronliu/zephyr,fractalclone/zephyr-riscv,erwango/zephyr,fbsder/zephyr,aceofall/zephyr-iotos,bboozzoo/zephyr,runchip/zephyr-cc3220,nashif/zephyr,erwango/zephyr,fractalclone/zephyr-riscv,punitvara/zephyr,bboozzoo/zephyr,fbsder/zephyr,zephyriot/zephyr,kraj/zephyr,punitvara/zephyr,erwango/zephyr,ldts/zephyr,galak/zephyr,runchip/zephyr-cc3220,holtmann/zephyr,Vudentz/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,kraj/zephyr,Vudentz/zephyr,holtmann/zephyr,GiulianoFranchetto/zephyr,runchip/zephyr-cc3200,ldts/zephyr,fractalclone/zephyr-riscv,aceofall/zephyr-iotos,rsalveti/zephyr,bigdinotech/zephyr,kraj/zephyr,rsalveti/zephyr,GiulianoFranchetto/zephyr,aceofall/zephyr-iotos,explora26/zephyr,zephyriot/zephyr,Vudentz/zephyr,galak/zephyr,explora26/zephyr,bigdinotech/zephyr,finikorg/zephyr,holtmann/zephyr,finikorg/zephyr,galak/zephyr,kraj/zephyr,explora26/zephyr,kraj/zephyr,runchip/zephyr-cc3200,erwango/zephyr,bboozzoo/zephyr,fractalclone/zephyr-riscv,zephyriot/zephyr,rsalveti/zephyr,holtmann/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,runchip/zephyr-cc3200,bigdinotech/zephyr,ldts/zephyr,runchip/zephyr-cc3220,fbsder/zephyr,mbolivar/zephyr,nashif/zephyr,ldts/zephyr,zephyriot/zephyr,nashif/zephyr,pklazy/zephyr,fractalclone/zephyr-riscv,bboozzoo/zephyr,pklazy/zephyr,galak/zephyr,punitvara/zephyr,holtmann/zephyr,runchip/zephyr-cc3220,punitvara/zephyr,runchip/zephyr-cc3220,GiulianoFranchetto/zephyr,erwango/zephyr,pklazy/zephyr,mbolivar/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,bigdinotech/zephyr,bigdinotech/zephyr,sharronliu/zephyr,explora26/zephyr,finikorg/zephyr