drm/aspeed: Add AST2600 chip support

Add AST2600 chip support and setting.
Signed-off-by: Tommy Haung <tommy_huang@aspeedtech.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Link: https://patchwork.freedesktop.org/patch/msgid/20220302024930.18758-5-tommy_huang@aspeedtech.com

drivers/gpu/drm/aspeed/aspeed_gfx_drv.c

@@ -83,9 +83,18 @@ static const struct aspeed_gfx_config ast2500_config = {
 	.scan_line_max = 128,
 };
 
+static const struct aspeed_gfx_config ast2600_config = {
+	.dac_reg = 0xc0,
+	.int_clear_reg = 0x68,
+	.vga_scratch_reg = 0x50,
+	.throd_val = CRT_THROD_LOW(0x50) | CRT_THROD_HIGH(0x70),
+	.scan_line_max = 128,
+};
+
 static const struct of_device_id aspeed_gfx_match[] = {
 	{ .compatible = "aspeed,ast2400-gfx", .data = &ast2400_config },
 	{ .compatible = "aspeed,ast2500-gfx", .data = &ast2500_config },
+	{ .compatible = "aspeed,ast2600-gfx", .data = &ast2600_config },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, aspeed_gfx_match);