This patch adds flexibility to the code to initialise multiple SMMU
devices. The base address macro name has been changed to make it
explicit that we support multiple SMMUs.

Change-Id: Id4854fb010ebeb699512d79c769de24050c2ad69
Signed-off-by: Pritesh Raithatha <praithatha@nvidia.com>
Signed-off-by: Krishna Reddy <vdumpa@nvidia.com>
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>