The DMA API provides dma_slot field as a method to configure at
runtime which peripheral DMA_request the DMA controller should
select.
This method allows to specify different selections for different stm32
DMA streams. So, all the Kconfig definitions, which by the way where
fixing the same selection for all DMA streams, have been deleted.
Signed-off-by: Armando Visconti <armando.visconti@st.com>