Rename cpu and dma addresses in wcn36xx_dxe_ch

Remove the meaningless prefix.
Fix some whitespace errors.

Signed-off-by: Pontus Fuchs <pontus.fuchs@gmail.com>
Clean up DMA allocations

Remove the wrapper function. It adds nothing but confusion.
Fix bad DMA free's as reported by Kalle Valo.

Signed-off-by: Pontus Fuchs <pontus.fuchs@gmail.com>