video: rockchip: vcodec: fix risk for session->type overflow

bug relative serial number: CNVD-C-2020-193874

Change-Id: I0862d1d43a2cd6be1ee51da5c1f22228e5ec074b
Signed-off-by: Ding Wei <leo.ding@rock-chips.com>

Author: WainDing

drivers/video/rockchip/vcodec/vcodec_service.c

@@ -43,6 +43,7 @@
 #include <linux/pm_opp.h>
 #include <linux/pm_runtime.h>
 #include <linux/iopoll.h>
+#include <linux/nospec.h>
 
 #include <linux/regulator/consumer.h>
 #include <linux/rockchip/grf.h>
@@ -1454,6 +1455,8 @@ static struct vpu_reg *reg_init(struct vpu_subdev_data *data,
 		extra_size = size - data->reg_size;
 		size = data->reg_size;
 	}
+	session->type = array_index_nospec(session->type, VPU_TYPE_BUTT);
+
 	reg->session = session;
 	reg->data = data;
 	reg->type = session->type;