Move general FAPI P5 message pack procedure from fapi_vnf_p5 into FAPI P5 library.

Implement FAPI P5 message unpack, as well as message length check function procedure in FAPI P5 library.
Update check_nr_unpack_length in nfapi_p5.c to reference FAPI P5 message length check function.

nfapi/open-nFAPI/fapi/inc/nr_fapi.h

@@ -40,8 +40,6 @@
 #include "nfapi.h"
 #include "assertions.h"
 
-#define DEBUG_FAPI_NFAPI_MSGS 0
-
 typedef struct {
   uint8_t num_msg;
   uint8_t opaque_handle;
@@ -49,4 +47,23 @@ typedef struct {
   uint32_t message_length;
 } fapi_message_header_t;
 
+int fapi_nr_p5_message_header_unpack(uint8_t **pMessageBuf,
+                                     uint32_t messageBufLen,
+                                     void *pUnpackedBuf,
+                                     uint32_t unpackedBufLen,
+                                     nfapi_p4_p5_codec_config_t *config);
+
+int fapi_nr_p5_message_pack(void *pMessageBuf,
+                            uint32_t messageBufLen,
+                            void *pPackedBuf,
+                            uint32_t packedBufLen,
+                            nfapi_p4_p5_codec_config_t *config);
+
+int fapi_nr_p5_message_unpack(void *pMessageBuf,
+                              uint32_t messageBufLen,
+                              void *pUnpackedBuf,
+                              uint32_t unpackedBufLen,
+                              nfapi_p4_p5_codec_config_t *config);
+
+int check_nr_fapi_unpack_length(nfapi_nr_phy_msg_type_e msgId, uint32_t unpackedBufLen);
 #endif // OPENAIRINTERFACE_NR_FAPI_H