include: zephyr: drivers: dma: fix STM32_DMA_GET_INSTANCE() macro

Add the STM32 auxiliary macro STM32_DMA_GET_CHANNEL_INSTANCE to handle
naming convention conflicts between STM32 series.
The H5, H7RS, N6, U3, MP2, U5, and WBA series use
the LL_DMA_GET_CHANNEL_INSTANCE definition, while other series use
__LL_DMA_GET_CHANNEL_INSTANCE.

Signed-off-by: Fabrice DJIATSA <fabrice.djiatsa-ext@st.com>