msm: vidc: Protect smem operations with core lock

When FW triggers a hardware error, it is possible that one
instance is trying to resurrect FW and another instance is
calling SMEM operations which are not protected by core lock
and it can end up making IOMMU calls when IOMMU is detached.

Change-Id: I735075f65007ad11ba7d1003c5ff7189d9ac0c93
Signed-off-by: Sachin Shah <sachins@codeaurora.org>