net: rmnet_data: add support for UL MAP based checksum offload

Add UL checksum offload routines for MAPv3. Can bypass checksum software
for IPv4/IPv6 TCP/UDP protocols.
Set rmnet_data VNDs hw_flags to NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM to
define the checksum offload abilities.
Add UL checksum meta-info header for IPv4/IPv6 TCP/UDP packets for which
UL checksum is being offloaded.

Change-Id: Ief139d357b528aead66acfe39a5227328b8fbf93
Signed-off-by: Sivan Reinstein <sivanr@codeaurora.org>
[subashab@codeaurora.org: Fix trivial merge conflicts in
net/rmnet_data/rmnet_data_trace.h]
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>