drivers: dma-removed: use memset_io for ioremap region

Using memset generates unaligned access exception for
device type memory on armv8, hence use memset_io for
ioremap region.

Change-Id: I26c82d4bed20f1c163953680aa200c95842d3f21
Signed-off-by: Shiraz Hashim <shashim@codeaurora.org>