x86. reboot: Make Dell Latitude E6320 use reboot=pci

The Dell Latitude E6320 doesn't reboot unless reboot=pci is set.
Force it thanks to DMI.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: http://lkml.kernel.org/r/1309269451-4966-1-git-send-email-maxime.ripard@free-electrons.com
Cc: Matthew Garrett <mjg@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>