drm/amd/display: Increase DP blank timeout from 30 ms to 50 ms

[Why]
At 24 Hz, a frame is 41.7 ms, so a 30 ms wait can (and does often)
timeout.

[How]
Bump timeout from 30 ms to 50 ms.

Signed-off-by: Ken Chalmers <[e-mail]>
Reviewed-by: Tony Cheng <[e-mail]>
Acked-by: Leo Li <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_stream_encoder.c

···
 	 */
 	REG_UPDATE(DP_VID_STREAM_CNTL, DP_VID_STREAM_DIS_DEFER, 2);
 	/* Larger delay to wait until VBLANK - use max retry of
-	 * 10us*3000=30ms. This covers 16.6ms of typical 60 Hz mode +
+	 * 10us*5000=50ms. This covers 41.7ms of minimum 24 Hz mode +
 	 * a little more because we may not trust delay accuracy.
 	 */
-	max_retries = DP_BLANK_MAX_RETRY * 150;
+	max_retries = DP_BLANK_MAX_RETRY * 250;
 
 	/* disable DP stream */
 	REG_UPDATE(DP_VID_STREAM_CNTL, DP_VID_STREAM_ENABLE, 0);