drm/amd/display: Check index for aux_rd_interval before using

aux_rd_interval has size of 7 and should be checked.

This fixes 3 OVERRUN and 1 INTEGER_OVERFLOW issues reported by Coverity.
Reviewed-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c

@@ -914,10 +914,10 @@ static enum dc_status configure_lttpr_mode_non_transparent(
 			/* Driver does not need to train the first hop. Skip DPCD read and clear
 			 * AUX_RD_INTERVAL for DPTX-to-DPIA hop.
 			 */
-			if (link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA)
+			if (link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA && repeater_cnt > 0 && repeater_cnt < MAX_REPEATER_CNT)
 				link->dpcd_caps.lttpr_caps.aux_rd_interval[--repeater_cnt] = 0;
 
-			for (repeater_id = repeater_cnt; repeater_id > 0; repeater_id--) {
+			for (repeater_id = repeater_cnt; repeater_id > 0 && repeater_id < MAX_REPEATER_CNT; repeater_id--) {
 				aux_interval_address = DP_TRAINING_AUX_RD_INTERVAL_PHY_REPEATER1 +
 						((DP_REPEATER_CONFIGURATION_AND_STATUS_SIZE) * (repeater_id - 1));
 				core_link_read_dpcd(