ANDROID: gki - enable CONFIG_USB_NET_CDC_EEM=y

CDC protocols in chronological order from oldest to newest:
  ECM - Ethernet Control Model
  EEM - Ethernet Emulation Model
  NCM - Network Control Model

We have CDC ECM (CDCETHER) and CDC NCM support already,
so also support the intermediate CDC EEM usb network protocol.

Some USB Ethernet dongles use this mode when there is
no native driver available.

Test: built and booted on a gki using phone
Bug: 183564444
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Ie34fc86b7243cf76edf39211e9f9359714414408