Change NBPG to PAGE_SIZE to match one of phk's recent commits.
Change NBPG to PAGE_SIZE to match one of phk's recent commits.

PR:		6573
Submitted by:	Kazuo Horikawa <horikawa@jp.freebsd.org>

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