ANDROID: GKI: enable some USB_NET_ config options

Vendors rely on USB networking devices for tethering, so enable:
	CONFIG_USB_NET_AX8817X
	CONFIG_USB_NET_AX88179_178A
	CONFIG_USB_NET_CDCETHER
as that provides a wide range of support for these types of devices.

Bug: 164154178
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I9f5d1d49ca819797dc951cc44691254747c09c06