msm: vidc: Allow venus to power collapse in batch mode

In batch mode Venus will be IDLE after sending EBD's and FBD's
to host. Power collapsing Venus at this time can save power.

CRs-Fixed: 1049499
Change-Id: I795d14fd4bc3b5f31897a70009546238117b0825
Signed-off-by: Praneeth Paladugu <ppaladug@codeaurora.org>