msm: vidc: Bail out of work handler if device is in DEINIT state

This change makes sure that worker thread doesn't handle any
interrupts if core is not in valid state.

Change-Id: If5493d277f4aa80df98640ed4c3854f34c12ad38
Signed-off-by: Sowmya Pandiri <spandiri@codeaurora.org>