ippool: Extend pool to work with /64 prefixes

In IPv6 GPRS, we actually don't want to allocate an individual v6
address (like in IPv4), but we want to allocate a prefix.  The
standard prefix lengh is 8 bytes, i.e. a /64 prefix.  This patch
extends the pool to be able to work with such v6 prefixes.

Change-Id: I0cf700b6baf195a2e5fbea000531f801acaaa443
diff --git a/lib/in46_addr.c b/lib/in46_addr.c
index a220583..1785377 100644
--- a/lib/in46_addr.c
+++ b/lib/in46_addr.c
@@ -25,6 +25,7 @@
 	switch (in->len) {
 	case 4:
 		return AF_INET;
+	case 8:
 	case 16:
 		return AF_INET6;
 	default:
@@ -175,6 +176,7 @@
 		eua->v[1] = 0x21;	/* IPv4 */
 		memcpy(&eua->v[2], &src->v4, 4);	/* Copy a 4 byte address */
 		break;
+	case 8:
 	case 16:
 		eua->l = 18;
 		eua->v[0] = 0xf1;	/* IETF */