ARM: dts: msm: Use SMR masks for iommus in FastRPC nodes for SDM855

Currently, there are about 50+ entries for iommus in FastRPC
device nodes. This is going to take 50+ SMR registers of SMMU.
Its a huge resource to be taken by just one client. Hence, shift
to using MASKs for the iommus property where ever possible to
reduce the entries.

Change-Id: I639136725ad5b118288eb23e4ec5c53b61157f0b
Signed-off-by: Sudarshan Rajagopalan <sudaraja@codeaurora.org>