The function configures additional features of the DMA stream for F2/F4/F7.
`dma_setup_ext` added to configure F2/F4/F7 specific additional features like `MBURST`, `PBURST`, `FIFO` and Peripheral flow controller. It is supposed to be used after `dma_setup` and `dma_prepare`.
As implmented, dma_resume assumed that transfers widths were 1 byte and
that the memory address incrmenting was always on and periphial address
incrementing always off. This resulted in memory corruption anytime
these assumptions were not true and a dma was resumed. The DMA module
allows intitiating transfers that did not meet these assumption.
This patch adds proper handling inside dma_resume to safely resume any
transfer. Clearifications and errors are added/fixed in the module's
header file. Also, a few constants are removed from the gobal namespace.
As it was, the calculation of DMA2's IRQ number was inccrorect for some
STM families. The implmentation alocates streams numbers 0 to 7 for the
first DMA controller and 8 and up for the second DMA controller. This
offset of +8 was not accounted for when IRQ's of the second DMA
controller was calculated. This patch corrects this.
