video: driver: introduce client lock

Acquire client lock for every entry point
in driver. This is needed especially for
streamoff and close calls where inst lock
is released while driver is waiting for
stop_done and close_done responses from fw.
When inst lock is released, client can send
a new ioctl call and driver state machine
can get updated leading to unexpected behaviour.

Change-Id: Ibb62c3431c88e2f1d9088d54fe7c9e53b1c284fd
Signed-off-by: Darshana Patil <quic_darshana@quicinc.com>

driver/vidc/inc/msm_vidc_inst.h

@@ -98,6 +98,7 @@ struct msm_vidc_inst {
 	struct list_head                   list;
 	struct mutex                       lock;
 	struct mutex                       request_lock;
+	struct mutex                       client_lock;
 	enum msm_vidc_inst_state           state;
 	enum msm_vidc_domain_type          domain;
 	enum msm_vidc_codec_type           codec;