dmaengine: coh901318: fix integer overflow when shifting more than 32 places

Currently U300_DMA_CHANNELS is set to 40, meaning that the shift of 1 can
be more than 32 places, which leads to a 32 bit integer overflow. Fix this
by using 1ULL instead of 1 before shifting it.  Also add braces on the
for-loop to keep with coding style conventions.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>