MFC: r198502
MFC: r198502

Sync with the other archs and wrap the prototype of in_cksum_skip(9)
in #ifdef _KERNEL.

Submitted by:	Ulrich Spoerlein

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase