gsm0808: remove redundant assert() in enc_speech_codec()

This assert can be dropped because the switch statement above does
not leave any sc->type >= 0x0f for type_extended == false.

Change-Id: Iafb45ed66378f2c9c2480f81371e92c6d1da71a7
diff --git a/src/gsm/gsm0808_utils.c b/src/gsm/gsm0808_utils.c
index 026a923..5b7fff2 100644
--- a/src/gsm/gsm0808_utils.c
+++ b/src/gsm/gsm0808_utils.c
@@ -264,7 +264,6 @@
 		msgb_put_u8(msg, header);
 		msgb_put_u8(msg, sc->type);
 	} else {
-		OSMO_ASSERT(sc->type < 0x0f);
 		header |= sc->type;
 		msgb_put_u8(msg, header);
 	}