Make function amr_is_octet_aligned publicly available

it will be used by mgcp_iuup.c in follow-up patch.

Change-Id: Iffaf90c1f713feef0c609a7581a346f5f28141d9
diff --git a/src/libosmo-mgcp/mgcp_codec.c b/src/libosmo-mgcp/mgcp_codec.c
index 7ab2a17..1b835c9 100644
--- a/src/libosmo-mgcp/mgcp_codec.c
+++ b/src/libosmo-mgcp/mgcp_codec.c
@@ -355,7 +355,7 @@
  *
  * https://tools.ietf.org/html/rfc4867
  */
-static bool amr_is_octet_aligned(const struct mgcp_rtp_codec *codec)
+bool mgcp_codec_amr_is_octet_aligned(const struct mgcp_rtp_codec *codec)
 {
 	if (!codec->param_present)
 		return false;
@@ -379,7 +379,7 @@
 	if (strcmp(codec_a->subtype_name, codec_b->subtype_name))
 		return false;
 	if (!strcmp(codec_a->subtype_name, "AMR")) {
-		if (amr_is_octet_aligned(codec_a) != amr_is_octet_aligned(codec_b))
+		if (mgcp_codec_amr_is_octet_aligned(codec_a) != mgcp_codec_amr_is_octet_aligned(codec_b))
 			return false;
 	}