libosmocodec: add FR/HR/EFR frame length definitions

There are some projects, such as OsmoBTS and OsmocomBB, which
are dealing with raw TCH payloads, so they need to have the
FR/HR/EFR frame length defined. At the moment, each project
defines them itself. Let's share these definitions.

Change-Id: Ib19dd1bf81712d034157f9ce061008be0000ef38
diff --git a/include/osmocom/codec/codec.h b/include/osmocom/codec/codec.h
index 3e62a01..6a1bf9f 100644
--- a/include/osmocom/codec/codec.h
+++ b/include/osmocom/codec/codec.h
@@ -7,6 +7,13 @@
 
 #include <osmocom/core/utils.h>
 
+/* TS 101318 Chapter 5.1: 260 bits + 4bit sig */
+#define GSM_FR_BYTES	33
+/* TS 101318 Chapter 5.2: 112 bits, no sig */
+#define GSM_HR_BYTES	14
+/* TS 101318 Chapter 5.3: 244 bits + 4bit sig */
+#define GSM_EFR_BYTES	31
+
 extern const uint16_t gsm610_bitorder[];	/* FR */
 extern const uint16_t gsm620_unvoiced_bitorder[]; /* HR unvoiced */
 extern const uint16_t gsm620_voiced_bitorder[];   /* HR voiced */