msm: camera isp: Control camif interrupts on camif enable/disable

Turn off the camif interrupts when camif is disabled and turn them
on when camif is enabled. Also, improve the code to keep track of
interrupts that are enabled by updating them in the function that
sets interrupts instead of doing it in multiple places.

CRs-Fixed: 1037272
Change-Id: I1cc965696c06bd3901d86668aaf597abb3ef2d6d
Signed-off-by: Shubhraprakash Das <sadas@codeaurora.org>