net: qualcomm: rmnet: Add support for GRO

Add gro_cells so that rmnet devices can call gro_cells_receive
instead of netif_receive_skb.

CRs-Fixed: 2156182
Change-Id: I6fc0bbc2ea13aa1c4f25425a44e65f365ac08d8c
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Git-commit: ca32fb034c19e00cfb5e0fd7217eb92f81302048
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>