gsm_08_08: gsm0808_permitted_speech does not have value strings

enum gsm0808_permitted_speech does not have any value strings. Lets
add value strings to make debugging easier.

Change-Id: I5b5612a5df2758b0137a34c17f7c8c2b3f07c806
diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index 96779d2..5eed5b5 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -201,6 +201,7 @@
 gsm0808_chan_type_to_speech_codec;
 gsm0808_speech_codec_from_chan_type;
 gsm0808_speech_codec_type_names;
+gsm0808_permitted_speech_names;
 gsm0808_channel_type_name;
 gsm0808_lcls_config_names;
 gsm0808_lcls_control_names;