drm/ast: Support 1600x900 with 108MHz PCLK

[New] Create the setting for 1600x900 @60Hz refresh rate
      by 108MHz pixel-clock.
Signed-off-by: KuoHsiang Chou <kuohsiang_chou@aspeedtech.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20201030074212.22401-1-kuohsiang_chou@aspeedtech.com

drivers/gpu/drm/ast/ast_tables.h

@@ -282,6 +282,8 @@ static const struct ast_vbios_enhtable res_1360x768[] = {
 };
 
 static const struct ast_vbios_enhtable res_1600x900[] = {
+	{1800, 1600, 24, 80, 1000,  900, 1, 3, VCLK108,		/* 60Hz */
+	 (SyncPP | Charx8Dot | LineCompareOff | WideScreenMode | NewModeInfo), 60, 3, 0x3A },
 	{1760, 1600, 48, 32, 926, 900, 3, 5, VCLK97_75,		/* 60Hz CVT RB */
 	 (SyncNP | Charx8Dot | LineCompareOff | WideScreenMode | NewModeInfo |
 	  AST2500PreCatchCRT), 60, 1, 0x3A },