drm/lima: fix lima_gem_wait() return value

drm_gem_reservation_object_wait() returns 0 if it succeeds and -ETIME
if it timeouts, but lima driver assumed that 0 is error.

Cc: stable@vger.kernel.org
Fixes: a1d2a633 ("drm/lima: driver for ARM Mali4xx GPUs")
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Qiang Yu <yuq825@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190908024800.23229-1-anarsoul@gmail.com

drivers/gpu/drm/lima/lima_gem.c

@@ -342,7 +342,7 @@ int lima_gem_wait(struct drm_file *file, u32 handle, u32 op, s64 timeout_ns)
 	timeout = drm_timeout_abs_to_jiffies(timeout_ns);
 
 	ret = drm_gem_reservation_object_wait(file, handle, write, timeout);
-	if (ret == 0)
+	if (ret == -ETIME)
 		ret = timeout ? -ETIMEDOUT : -EBUSY;
 
 	return ret;