msm: vidc: Remove deprecated iommu initialization apis

IOMMU initialization APIs have been deprecated and replaced by
device tree properties. IOMMU driver will map/unmap and
attach/detach device at bootup, based on the dtsi entries.

CRs-Fixed: 2358497
Change-Id: I2be820ed406c46209e927e5f7f861e75d67e966a
Signed-off-by: Chinmay Sawarkar <chinmays@codeaurora.org>