DMAENGINE: Set burst size for phy and log chans in ste_dma40 dev_control

Set burst for physical or logical channels respectively.
Convert the values in dma_cfg to dma reg bits
for physical or logical channels.

Signed-off-by: Per Forlin <per.forlin@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>