msm: vidc: Fix power collapse issue

Video firmware will set the idle status bit only when
video driver enables idle indicator else video firmware
will not set idle status bit. So check idle indicator before
verifying idle status bit in power collapse sequence to avoid
skipping power collapse.

CRs-Fixed: 2034063
Change-Id: I6a2890af7fda883daf890596728ea7133e4bbf46
Signed-off-by: Maheshwar Ajja <majja@codeaurora.org>