rules: Add symlink rule for virtio ports

virtio ports spawned by the virtio_console.c driver can have 'names'
assigned to them by hosts. The ports are distinguishable using these
names. Make a rule to create a symlink to the chardev associated for a
port with a name.

The symlink created is:
    /dev/virtio-ports/org.libvirt.console0 -> /dev/vport0p0

if the first port for the first device was given a name of
'org.libvirt.console0'.

Signed-off-by: Amit Shah <amit.shah@redhat.com>

rules/rules.d/50-udev-default.rules

@@ -17,6 +17,9 @@ KERNEL=="ppp",			MODE="0600"
 KERNEL=="mwave",		GROUP="dialout"
 KERNEL=="hvc*|hvsi*",		GROUP="dialout"
 
+# virtio serial / console ports
+KERNEL=="vport*", SYMLINK+="virtio-ports/$ATTR{name}"
+
 # mem
 KERNEL=="null|zero|full|random|urandom", MODE="0666"
 KERNEL=="mem|kmem|port|nvram",	GROUP="kmem", MODE="0640"