Remove NLS support from BSD grep

GNU grep as in actually in base does not have any translations support
compiled in, so no functionnality loss.

We do support 193 locales in base, we will never catch up on that number of
translation with bsd grep.

Removing NLS support make bsd grep consistent with the other binaries in base
which are not translated, and also reduce a little bit the code.

Reviewed by: kevans
Approved by: kevans
Discussed with: kevans @BSDCan
Differential Revision: https://reviews.freebsd.org/D15682