drm/ast: Create chip AST2600

[New] Support AST2600
Signed-off-by: KuoHsiang Chou <kuohsiang_chou@aspeedtech.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20201109093812.161483-1-kuohsiang_chou@aspeedtech.com

drivers/gpu/drm/ast/ast_drv.h

@@ -64,6 +64,7 @@ enum ast_chip {
 	AST2300,
 	AST2400,
 	AST2500,
+	AST2600,
 };
 
 enum ast_tx_chip {

drivers/gpu/drm/ast/ast_main.c

@@ -143,7 +143,10 @@ static int ast_detect_chip(struct drm_device *dev, bool *need_post)
 	ast_detect_config_mode(dev, &scu_rev);
 
 	/* Identify chipset */
-	if (dev->pdev->revision >= 0x40) {
+	if (dev->pdev->revision >= 0x50) {
+		ast->chip = AST2600;
+		drm_info(dev, "AST 2600 detected\n");
+	} else if (dev->pdev->revision >= 0x40) {
 		ast->chip = AST2500;
 		drm_info(dev, "AST 2500 detected\n");
 	} else if (dev->pdev->revision >= 0x30) {