Add hypervisor consoles (hvc)

Add /dev/hvc* devices, and add them to securetty. These
are required for ppc64 virtual consoles.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

system/device_table_dev.txt

@@ -36,6 +36,7 @@
 /dev/ttyPSC	c	666	0	0	204	148	0	1	4
 /dev/ttyUL	c	666	0	0	204	187	0	1	4
 /dev/ttymxc	c	666	0	0	207	16	0	1	4
+/dev/hvc	c	640	0	0	229	0	0	1	4
 
 # Input stuff
 /dev/input		d	755	0	0	-	-	-	-	-

system/skeleton/etc/securetty

@@ -51,3 +51,7 @@ ttySC5
 ttySC6
 ttySC7
 ttyGS0
+hvc0
+hvc1
+hvc2
+hvc3