msm: vidc: Ping hardware during timeouts

Added PING command. Send the command to video firmware
when any awaited response is not received within the
stipulated time.
PING would help firmware to check if some commands or
messages are not processed in queue. At the same time,
the interrupts for handling PING command would clear
up the queues processing, if any.

Change-Id: Iee981dde3b3a1a21b74639703f86881fd5779027
Signed-off-by: Vikash Garodia <vgarodia@codeaurora.org>
Signed-off-by: Govindaraj Rajagopal <grajagop@codeaurora.org>