gadget: rockchip: USB_GADGET_PRODUCT_NUM

Rockchip support differnet or common gadget product number
between Rockchip SoCs like,

0x310a - rk3036
0x320a - rk3229, rk3288
0x330a - rk3328

So, select them on Kconfig based on platform specific
config defined.
   
This eventually drop the explicit configs defined in
supporting board defconfig files.

Tested-by: Levin Du <djw@t-chip.com.cn>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 844c3be..e120b48 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -58,6 +58,9 @@
 config USB_GADGET_PRODUCT_NUM
 	hex "Product ID of the USB device"
 	default 0x1010 if ARCH_SUNXI
+	default 0x310a if ROCKCHIP_RK3036
+	default 0x320a if ROCKCHIP_RK3229 || ROCKCHIP_RK3288
+	default 0x330a if ROCKCHIP_RK3328
 	default 0x0
 	help
 	  Product ID of the USB device emulated, reported to the host device.