drm/amd/powerplay: Off by one in vega20_get_smu_msg_index()

The > should be >= so that we don't read one element beyond the end of
the vega20_message_map[] array.

Fixes: 78031c2c ("drm/amd/powerplay: implement smu vega20_message_map for vega20")
Reviewed-by: Kevin Wang <kevin1.wang@amd.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/powerplay/vega20_ppt.c

@@ -132,7 +132,8 @@ static int vega20_message_map[SMU_MSG_MAX_COUNT] = {
 static int vega20_get_smu_msg_index(struct smu_context *smc, uint32_t index)
 {
 	int val;
-	if (index > SMU_MSG_MAX_COUNT)
+
+	if (index >= SMU_MSG_MAX_COUNT)
 		return -EINVAL;
 
 	val = vega20_message_map[index];