gadget: Select USB_GADGET_VENDOR_NUM for rockchip

Gadget vendor number, 0x2207 is common across all platfroms
supported in Rockchip SoC.

So, select the same number globally, if ARCH_ROCKCHIP.

This eventually drop the explicit configs defined in supported
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 1959a39..844c3be 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -48,6 +48,7 @@
 config USB_GADGET_VENDOR_NUM
 	hex "Vendor ID of the USB device"
 	default 0x1f3a if ARCH_SUNXI
+	default 0x2207 if ARCH_ROCKCHIP
 	default 0x0
 	help
 	  Vendor ID of the USB device emulated, reported to the host device.