turn abis_nm_debugp_foh() into a macro

this will avoid printing 'abis_nm.c' as the filename in the log, which
is pretty useless during debugging.  We want to know where
abis_nm_debugp_foh() is being used from, not where it is implemented.
diff --git a/include/osmocom/gsm/abis_nm.h b/include/osmocom/gsm/abis_nm.h
index 320ac3e..e2b941f 100644
--- a/include/osmocom/gsm/abis_nm.h
+++ b/include/osmocom/gsm/abis_nm.h
@@ -30,7 +30,17 @@
 const char *abis_nm_opstate_name(uint8_t os);
 const char *abis_nm_avail_name(uint8_t avail);
 const char *abis_nm_test_name(uint8_t test);
-void abis_nm_debugp_foh(int ss, struct abis_om_fom_hdr *foh);
+
+/*! \brief write a human-readable OML header to the debug log
+ *  \param[in] ss Logging sub-system
+ *  \param[in] foh A-bis OML FOM header
+ */
+#define abis_nm_debugp_foh(ss, foh)					    \
+	DEBUGP(ss, "OC=%s(%02x) INST=(%02x,%02x,%02x) ",		    \
+		get_value_string(abis_nm_obj_class_names, foh->obj_class),  \
+		foh->obj_class, foh->obj_inst.bts_nr, foh->obj_inst.trx_nr, \
+		foh->obj_inst.ts_nr)
+
 
 int abis_nm_chcomb4pchan(enum gsm_phys_chan_config pchan);
 enum abis_nm_chan_comb abis_nm_pchan4chcomb(uint8_t chcomb);