HDMI : Refine the clock limitation from 594000 to 300000 to prevent the 4k@59.94Hz show up

We didn't support the 4k@60, so the item 4k@59.94Hz is invalid.

Change-Id: I7a7544caf5f5f9b9ecfa56e1422e6d68c242622b
Reviewed-on: https://tp-biosrd-v02/gerrit/82102
Reviewed-by: Jamess Huang(黃以民) <Jamess_Huang@asus.com>
Tested-by: Jamess Huang(黃以民) <Jamess_Huang@asus.com>

Author: ashinlin

drivers/gpu/drm/rockchip/rockchip_drm_vop.c

@@ -2056,7 +2056,7 @@ vop_crtc_mode_valid(struct drm_crtc *crtc, const struct drm_display_mode *mode,
 	int request_clock = mode->clock;
 	int clock;
 
-	if (mode->clock >= 594000 || mode->clock <= 27500)
+	if (mode->clock >= 300000 || mode->clock <= 27500)
 		return MODE_CLOCK_RANGE;
 
 	if (mode->hdisplay > vop_data->max_output.width)