net: qualcomm: rmnet: Add NETIF_F_GRO_HW support

When the NETIF_F_GRO_HW bit is set in the device features, we no longer
need to rebuild every packet in a hardware coalesced frame. Instead, we
send larger SKBs made up of multiple packets that hardware has coalesced
for us.

When sending these large packets, we fill in the various extra metadata
needed by the network stack so that way the larger packets can be properly
broken up if need be during forwarding, or during the UDP GRO path before
queueing the data to the socket.

Change-Id: I014d2095e838ec71ca3588e5b510f7652f22375f
Signed-off-by: Sean Tranchetti <stranche@codeaurora.org>