net: ipa: enable inline checksum offload for IPA v4.5+

The RMNet and IPA drivers both support inline checksum offload now.
So enable it for the TX and RX modem endoints for IPA version 4.5+.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>