MFC r250509:
	The M_VESA_MODE_MAX is latest valid mode - not the first invalid.
	Permit its use in vidcontrol -i

PR:		bin/119483


git-svn-id: svn+ssh://svn.freebsd.org/base/stable/8@250730 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f