dma: stm32: Configure bus width and burst size for memcpy mode
dma: stm32: Configure bus width and burst size for memcpy mode

In order to make use of the configurable bus width and burst size
options in memcpy mode, lets add configurations bits for the same.

This configuration is derived from the TRM of STM32F446xx Page No. 210
"Memory-to-memory mode" section and verified on 96Boards STM32 Sensor
Mezzanine board.

Signed-off-by: Manivannan Sadhasivam <7cdffa2a61f6c51ff0ae24b4793b8c7f31d1b1b0@linaro.org>

galak/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,explora26/zephyr,GiulianoFranchetto/zephyr,GiulianoFranchetto/zephyr,finikorg/zephyr,Vudentz/zephyr,ldts/zephyr,finikorg/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,explora26/zephyr,punitvara/zephyr,explora26/zephyr,Vudentz/zephyr,Vudentz/zephyr,punitvara/zephyr,explora26/zephyr,punitvara/zephyr,Vudentz/zephyr,ldts/zephyr,galak/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,punitvara/zephyr,nashif/zephyr,finikorg/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,explora26/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,nashif/zephyr,galak/zephyr,ldts/zephyr,galak/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,punitvara/zephyr,zephyrproject-rtos/zephyr