gsm/gsm0503.h: fix typo

Change-Id: I263d61111544eeb7227e1e0e8f2d14479eae2079
diff --git a/include/osmocom/gsm/gsm0503.h b/include/osmocom/gsm/gsm0503.h
index cf1c976..2da4b16 100644
--- a/include/osmocom/gsm/gsm0503.h
+++ b/include/osmocom/gsm/gsm0503.h
@@ -26,7 +26,7 @@
 
 #include <osmocom/core/conv.h>
 
-/*! \file conv_gen.h
+/*! \file gsm0503.h
  * Osmocom convolutional encoder/decoder for xCCH channels, see 3GPP TS 05.03
  */