dmaengine: fsl-edma: fix macros

This patch fixes macros to use BIT() and GENMASK(), removing
also some unneeded.

Signed-off-by: Angelo Dureghello <angelo@sysam.it>
Tested-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>