usb: gadget: aspeed: add ast2600 vhub support

Add AST2600 support in aspeed-vhub driver. There are 3 major differences
between AST2500 and AST2600 vhub:
  - AST2600 supports 7 downstream ports while AST2500 supports 5.
  - AST2600 supports 21 generic endpoints while AST2500 supports 15.
  - EP0 data buffer's 8-byte DMA alignment restriction is removed from
    AST2600.
Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

drivers/usb/gadget/udc/aspeed-vhub/Kconfig

@@ -4,5 +4,5 @@ config USB_ASPEED_VHUB
 	depends on ARCH_ASPEED || COMPILE_TEST
 	depends on USB_LIBCOMPOSITE
 	help
-	  USB peripheral controller for the Aspeed AST2500 family
-	  SoCs supporting the "vHub" functionality and USB2.0
+	  USB peripheral controller for the Aspeed AST2400, AST2500 and
+	  AST2600 family SoCs supporting the "vHub" functionality and USB2.0

drivers/usb/gadget/udc/aspeed-vhub/core.c

@@ -423,6 +423,9 @@ static const struct of_device_id ast_vhub_dt_ids[] = {
 	{
 		.compatible = "aspeed,ast2500-usb-vhub",
 	},
+	{
+		.compatible = "aspeed,ast2600-usb-vhub",
+	},
 	{ }
 };
 MODULE_DEVICE_TABLE(of, ast_vhub_dt_ids);