[media] exynos-gsc: Don't use mutex_lock_interruptible() in device release()

Use uninterruptible mutex_lock in the release() file op to make
sure all resources are properly freed when a process is being
terminated. Returning -ERESTARTSYS has no effect for a terminating
process and this may cause driver resources not to be released.
Reported-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/platform/exynos-gsc/gsc-m2m.c

@@ -657,8 +657,7 @@ static int gsc_m2m_release(struct file *file)
 	pr_debug("pid: %d, state: 0x%lx, refcnt= %d",
 		task_pid_nr(current), gsc->state, gsc->m2m.refcnt);
 
-	if (mutex_lock_interruptible(&gsc->lock))
-		return -ERESTARTSYS;
+	mutex_lock(&gsc->lock);
 
 	v4l2_m2m_ctx_release(ctx->m2m_ctx);
 	gsc_ctrls_delete(ctx);