ARM: dts: msm: add secure smmu cb node for sdm845

This change adds the secure context bank child node in mdss
driver, this is required for having both the secure and non-secure
smmu context bank support in the driver. This change also renames
the child nodes to avoid compilation issues on the builds, where
fb driver mdss device file is also present. As a part of this
change the smmu driver registration is called as a part of
msm driver probe.

CRs-Fixed: 2050484
Change-Id: I90cd31fd792b0fd9772689dc6561bb0b429e1e3a
Signed-off-by: Abhijit Kulkarni <kabhijit@codeaurora.org>