drm/amdgpu/mmhub3.0.1: add bounds checking for cid

commit 5d4e88b 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 5f76083183363c4528a4aaa593f5d38c28fe7d7b)
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: alexdeucher

drivers/gpu/drm/amd/amdgpu/mmhub_v3_0_1.c

@@ -117,7 +117,8 @@ mmhub_v3_0_1_print_l2_protection_fault_status(struct amdgpu_device *adev,
 
 	switch (amdgpu_ip_version(adev, MMHUB_HWIP, 0)) {
 	case IP_VERSION(3, 0, 1):
-		mmhub_cid = mmhub_client_ids_v3_0_1[cid][rw];
+		mmhub_cid = cid < ARRAY_SIZE(mmhub_client_ids_v3_0_1) ?
+			mmhub_client_ids_v3_0_1[cid][rw] : NULL;
 		break;
 	default:
 		mmhub_cid = NULL;