coding: fix API doc: TCH/AFS vs TCH/AHS

Change-Id: Iaed1653c6001545f69ec6b466760f30d42bc4386
diff --git a/src/coding/gsm0503_coding.c b/src/coding/gsm0503_coding.c
index f27b13d..f42deb2 100644
--- a/src/coding/gsm0503_coding.c
+++ b/src/coding/gsm0503_coding.c
@@ -2633,7 +2633,7 @@
 	return id;
 }
 
-/*! Perform channel decoding of a TCH/AFS channel according TS 05.03
+/*! Perform channel decoding of a TCH/AHS channel according TS 05.03
  *  \param[out] tch_data Codec frame in RTP payload format
  *  \param[in] bursts buffer containing the symbols of 6 bursts
  *  \param[in] odd Is this an odd (1) or even (0) frame number?
@@ -2656,7 +2656,7 @@
 					  n_bits_total, NULL);
 }
 
-/*! Perform channel decoding of a TCH/AFS channel according TS 05.03
+/*! Perform channel decoding of a TCH/AHS channel according TS 05.03
  *  \param[out] tch_data Codec frame in RTP payload format
  *  \param[in] bursts buffer containing the symbols of 6 bursts
  *  \param[in] odd Is this an odd (1) or even (0) frame number?