video-driver: Add Null Pointer check for response_workq

Add Null Pointer check for response_workq inside
cancel_response_work_sync function.

Change-Id: I574034b8937ade601cb9cda3f91c3c3bcf2c3e1e
Signed-off-by: Vedang Nagar <[email protected]>

driver/vidc/src/venus_hfi_response.c

@@ -1898,7 +1898,7 @@ int cancel_response_work(struct msm_vidc_inst *inst)
 
 int cancel_response_work_sync(struct msm_vidc_inst *inst)
 {
-	if (!inst) {
+	if (!inst || !inst->response_workq) {
 		d_vpr_e("%s: Invalid arguments\n", __func__);
 		return -EINVAL;
 	}