msm: vidc: Add support to align with legacy SMMU driver

This change adds support to parse iommu domains, if present
in legacy DT binding format. Create device pointer for each
context bank to keep track of mapping information.
Add the bus client entries in target dtsi file as per the
format parsed by video driver.

Change-Id: Ibcc5e0bf4e0ed801acdc809a036f7d220c64dfe4
Signed-off-by: Vikash Garodia <vgarodia@codeaurora.org>