share/mk: Include libbnxtre entry in bsd.libnames.mk

Add libbnxtre entry in bsd.libnames.mk file.

MFC-After: 3 days
Reviewed-by: sumit.saxena@broadcom.com
Differential-Revision: https://reviews.freebsd.org/D49603
(cherry picked from commit b42fda6be3fde001cdbe1623cc89b1dc9faf1b93)