Modifying smmu macros to pass base address of smmu so that it can be
used with multiple smmus.

Added macro for combining smmu backup regs that can be used for multiple
smmus.

Change-Id: I4f3bb83d66d5df14a3b91bc82f7fc26ec8e4592e
Signed-off-by: Pritesh Raithatha <praithatha@nvidia.com>