Update review requests for bhyve.

- Explicitly mention the #bhyve group on Phabricator.
- Request reviews of the userland components (libvmmapi, bhyve,
  bhyvectl, and bhyveload).

Reviewed by:	imp, rgrimes
Differential Revision:	https://reviews.freebsd.org/D17848

MAINTAINERS

@@ -106,7 +106,12 @@ usr.sbin/bsdconfig	dteske	Pre-commit phabricator review requested.
 usr.sbin/dpv	dteske	Pre-commit review requested. Keep in sync with libdpv.
 usr.sbin/pkg	pkg@	Please coordinate behavior or flag changes with pkg team.
 usr.sbin/sysrc	dteske	Pre-commit phabricator review requested. Keep in sync with bsdconfig(8) sysrc.subr.
-vmm(4)		tychon, jhb	Pre-commit review requested.
+vmm(4)		tychon, jhb	Pre-commit review requested via #bhyve
+				phabricator group.
+libvmmapi	tychon, jhb	Pre-commit review requested via #bhyve
+				phabricator group.
+usr.sbin/bhyve*	tychon, jhb	Pre-commit review requested via #bhyve
+				phabricator group.
 autofs(5)	trasz	Pre-commit review recommended.
 iscsi(4)	trasz	Pre-commit review recommended.
 rctl(8)		trasz	Pre-commit review recommended.