Previous defconfig for dma is DMA_STM32F4X in this board, while the new
generic driver uses DMA_STM32 to enable DMA support, and also dma driver
of stm32 now needs HEAP_MEM_POOL_SIZE to be big enough to hold dma
stream instances.
Additional .conf files are added for also adding HEAP_MEM_POOL_SIZE
configuration to two test cases.
Signed-off-by: Song Qiang <songqiang1304521@gmail.com>
