drm/amdgpu/mmhub3.0: add bounds checking for cid

commit cdb82ec upstream.

The value should never exceed the array size as those
are the only values the hardware is expected to return,
but add checks anyway.

Reviewed-by: Benjamin Cheng <benjamin.cheng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit f14f27bbe2a3ed7af32d5f6eaf3f417139f45253)
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: alexdeucher

drivers/gpu/drm/amd/amdgpu/mmhub_v3_0.c

@@ -110,7 +110,8 @@ mmhub_v3_0_print_l2_protection_fault_status(struct amdgpu_device *adev,
 	switch (amdgpu_ip_version(adev, MMHUB_HWIP, 0)) {
 	case IP_VERSION(3, 0, 0):
 	case IP_VERSION(3, 0, 1):
-		mmhub_cid = mmhub_client_ids_v3_0_0[cid][rw];
+		mmhub_cid = cid < ARRAY_SIZE(mmhub_client_ids_v3_0_0) ?
+			mmhub_client_ids_v3_0_0[cid][rw] : NULL;
 		break;
 	default:
 		mmhub_cid = NULL;