drm/amd/display: Don't check seamless boot in power down HW by timeout

[Why]
power_down_on_boot is designed to power down HW when set mode is not
called before timeout. It can happen in headless system or booting with
the display is output by non-AMD GPU only.
The function will be executed only if it's not seamless boot. So in
seamless boot, the HW is still on.
It's not necessary to check this since there's no display data in both
cases.

[How]
Remove seamless boot checking in power_down_on_boot.
Signed-off-by: John Wu <john.wu@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Eryk Brol <eryk.brol@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c

@@ -1442,16 +1442,13 @@ void dcn10_init_hw(struct dc *dc)
 /* In headless boot cases, DIG may be turned
  * on which causes HW/SW discrepancies.
  * To avoid this, power down hardware on boot
- * if DIG is turned on and seamless boot not enabled
+ * if DIG is turned on
  */
 void dcn10_power_down_on_boot(struct dc *dc)
 {
 	int i = 0;
 	struct dc_link *edp_link;
 
-	if (!dc->config.power_down_display_on_boot)
-		return;
-
 	edp_link = get_edp_link(dc);
 	if (edp_link &&
 			edp_link->link_enc->funcs->is_dig_enabled &&