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: I7012937c1aba2b292bd336e68f8463c401980d2a
Signed-off-by: Paras Nagda <pnagda@codeaurora.org>