drm/amdgpu/mmhub4.2.0: add bounds checking for cid

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 dea5f23)
Cc: stable@vger.kernel.org

Author: alexdeucher

drivers/gpu/drm/amd/amdgpu/mmhub_v4_2_0.c

@@ -688,7 +688,8 @@ mmhub_v4_2_0_print_l2_protection_fault_status(struct amdgpu_device *adev,
 		status);
 	switch (amdgpu_ip_version(adev, MMHUB_HWIP, 0)) {
 	case IP_VERSION(4, 2, 0):
-		mmhub_cid = mmhub_client_ids_v4_2_0[cid][rw];
+		mmhub_cid = cid < ARRAY_SIZE(mmhub_client_ids_v4_2_0) ?
+			mmhub_client_ids_v4_2_0[cid][rw] : NULL;
 		break;
 	default:
 		mmhub_cid = NULL;