drivers: stm32: Keep DMA stream offset handling internal to driver

In HAL based stm32 drivers, dma handling is done internally to HAL.
Though, in order to avoid a dma_config() call is done to ensure stream
will be set as busy in zephyr dma driver to avoid potential resource
sharing conflict.
This dma_config() call was done while taking into account
STM32_DMA_STREAM_OFFSET, which is wrong as it will prevent zephyr dma
driver to set the right stream as busy.
Fix this in impacted drivers.

Signed-off-by: Erwan Gouriou <erwan.gouriou@st.com>