net: ether: Add support for multiplexing and aggregation type

Define the Qualcomm multiplexing and aggregation (MAP) ether type 0x00F9.
This is needed for receiving data in the MAP protocol like RMNET. This is
not an officially registered ID.

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>