MFC: Elan support;

o Recognize AMD Elan SC520 hostbridge.
o Add initialization code for the AMD Elan sc520 which maps the MMCR
  into KVM and sets the i8254 frequency to the correct value.
o MAKEDEV entry for elan-mmcr device

Reviewed by:	phk, jhb
Approved by:	re(jhb)

etc/MAKEDEV

@@ -152,6 +152,7 @@
 #	agpgart	AGP interface
 #	cfs*	Coda Distributed Filesystem
 #	nsmb*	SMB/CIFS protocol interface
+#	elan-mmcr	AMD Elan support (e.g. mmap MMCR)
 #
 
 if [ -n "$MAKEDEVPATH" ]; then
@@ -1764,6 +1765,11 @@ nsmb*)
 	mknod nsmb$unit c 144 $unit
 	;;
 
+elan*)
+	mknod elan-mmcr c 100 0	# XXX local major
+	chmod 600 elan-mmcr
+	;;
+
 local)
 	umask 0			# XXX should be elsewhere
 	sh $0.local