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: Ia2c22a2740466e6368e61437aa4246927150858b
Signed-off-by: Maheshwar Ajja <majja@codeaurora.org>
Signed-off-by: Sanjay Singh <sisanj@codeaurora.org>