iommu/arm-smmu: Replace devm_ioremap_resource by devm_ioremap

Same tcu-base is used across gfx and apps smmu. Avoid reserving the
region and use devm_ioremap instead.

Change-Id: I99beeca30877069a8ea8c48f999d1f715fdac6ef
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>