db: extend database schema to support 256bit K and/or OP[c] values

Other UMTS AKA algorithms than MILENAGE (notably TUAK) support K sizes
of up to 256bit, or mandate a OP/OPc size of 256 bit.

Let's extend our database schema to accommodate such larger sizes.

Change-Id: Ibbde68484c904507a15c35cbfdf88cd47d0c7039
diff --git a/src/db_hlr.c b/src/db_hlr.c
index 8dfbb15..aa2e365 100644
--- a/src/db_hlr.c
+++ b/src/db_hlr.c
@@ -1,4 +1,4 @@
-/* (C) 2015 by Harald Welte <laforge@gnumonks.org>
+/* (C) 2015-2023 by Harald Welte <laforge@gnumonks.org>
  *
  * All Rights Reserved
  *
@@ -286,12 +286,12 @@
 
 		if (aud->algo == OSMO_AUTH_ALG_NONE)
 			break;
-		if (!osmo_is_hexstr(aud->u.umts.k, 32, 32, true)) {
+		if (!osmo_is_hexstr(aud->u.umts.k, 32, 64, true)) {
 			LOGP(DAUC, LOGL_ERROR, "Cannot update auth tokens:"
 			     " Invalid K: '%s'\n", aud->u.umts.k);
 			return -EINVAL;
 		}
-		if (!osmo_is_hexstr(aud->u.umts.opc, 32, 32, true)) {
+		if (!osmo_is_hexstr(aud->u.umts.opc, 32, 64, true)) {
 			LOGP(DAUC, LOGL_ERROR, "Cannot update auth tokens:"
 			     " Invalid OP/OPC: '%s'\n", aud->u.umts.opc);
 			return -EINVAL;