msm: vidc: ignore processing responses in invalid state

No need to process response messages from video hardware
after device went into invalid state. Processing responses
may result in use-after-free memory fault because client
might free all the resources after error.

Change-Id: I3bfb26e5aa52aba33b7b62cda7820dcbc5fe033f
Signed-off-by: Darshan Kumsi Srinivasa <darssr@codeaurora.org>