dt-bindings: msm: name changes in support of new smmu usage design

These changes reflect the new way of doing SMMU setup and usage.

Change-Id: I5d5493b32c0d0bd955c62a09026a3e97720d3e44
CRs-Fixed: 2398133
Signed-off-by: Perry Randise <prandise@codeaurora.org>