[PowerPC64LE] Use correct in_masks table on LE to fix checksumming

Due to a check that should have been an endian check being an #if 0,
the wrong checksum mask table was being used on LE, which was causing
extreme strangeness in DNS resolution -- *some* hosts would be resolvable,
but most would not.

This fixes DNS resolution.

(I am committing some parts of the LE patchset ahead of time to reduce the
amount of work I have to do while committing the main patchset.)

Sponsored by: Tag1 Consulting, Inc.