agp: Handle multiple devices more gracefully

Currently agp(4) effectively assumes that only one driver instance
exists, as the generic attach routine attempts to create /dev/agpgart
and triggers a panic if it already exists.  Instead, handle this
situation by creating /dev/agpgart<unit> and making /dev/agpgart an
alias of /dev/agpgart0 for compatibility.

PR:		187015
Reviewed by:	imp, kib
Tested by:	Yoshihiro Ota <ota@j.email.ne.jp> (earlier version)
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D33068

0 files changed, 0 insertions, 0 deletions