hcksum routines are too verbose
Upstreaming OS-6761 for bhyve:
hcksum_retreivefunctions feature special handling for
M_MULTIDATAmblks which are no longer used by anything in the gate. Removing that logic would make their calls less verbose and marginally decrease the amount of work they must undertake.
It turns out that some closed drivers that we ship make use of those old functions so they can't be changed. Switching in-gate consumers to the (more recent) mac_hcksum_* counterparts is an adequate substitute.
I tested the fix for this (and OS-6762) with workloads running with and without VLANs between instances. Additionally, I floated the expected patch for OS-6701 over the top to further test the mac_hcksum_clone function, as it's essential to that fix. It worked as desired, too.