x86: Add reboot quirk for 3 series Mac mini

Reboot does not work out of the box on my "Early 2009" Mac mini
(3,1). Detect this machine via DMI as we do for recent MacBooks.

Signed-off-by: Gottfried Haider <gottfried.haider@gmail.com>
Cc: Ozan Çağlayan <ozan@pardus.org.tr>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>