msm: vidc: Enable workmode 2 for RC_OFF

To support 4k@60fps RC_OFF usecases, work mode 2
is required to enable video session to schedule
on dual core i.e 4k@30 on each core.

Change-Id: I67b0936e996e2e439e8cdc309e818e7a718d76d5
Signed-off-by: Mahesh Voorugonda <mvoorugo@codeaurora.org>