iommu: msm: fix checkpatch errors

Fix lot of checkpatch reported errors in legacy msm iommu
driver, few cases are still left out due to relevance or
impact on simplicity.

Change-Id: I273e9d27aaa3856f092f180cdbffc2d1cda98b7b
Signed-off-by: Shiraz Hashim <shashim@codeaurora.org>