cosmetic: icmpv6.c: fix typo in comment

Change-Id: I2217dfb0b0a1e6e029ac817902e80c771ed219c3
diff --git a/lib/icmpv6.c b/lib/icmpv6.c
index a6545fd..63acc0e 100644
--- a/lib/icmpv6.c
+++ b/lib/icmpv6.c
@@ -161,7 +161,7 @@
 	return msg;
 }
 
-/* Walidate an ICMPv6 router solicitation according to RFC4861 6.1.1 */
+/* Validate an ICMPv6 router solicitation according to RFC4861 6.1.1 */
 static bool icmpv6_validate_router_solicit(const uint8_t *pack, unsigned len)
 {
 	const struct ip6_hdr *ip6h = (struct ip6_hdr *)pack;