ANDROID: gki - enable CONFIG_USB_RTL8150=y

This is to support ethernet usb dongle:
  Realtek RTL8150 USB 10/100 Fast Ethernet Adapter

This is supported by pre-GKI Pixel devices, and the lack of support
in GKI kernels appears to simply be an oversight.

Test: built and booted on a gki using phone
Bug: 183564444
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Ief6cb29facc0b9b98d9c83897d2e88e0aa83be58