msm: camera: isp: Process pagefault in callback function

Process an IOMMU pagefault in callback function instead of queueing
a tasklet. Also, in case of dual vfe halt the other VFE as well
if pagefault occurs on 1 vfe.

Change-Id: I86a9745f004c7891373709459ca98193a13f0f62
Signed-off-by: Shubhraprakash Das <sadas@codeaurora.org>
Signed-off-by: Jing Zhou <jzhou70@codeaurora.org>