Move RETURN_IF_INVALID_ASSOC_ID() to header for use elsewhere

RETURN_IF_INVALID_ASSOC_ID() checks if an assoc_id (of a DU) is valid.
It will be also used in the mobility RRC module later. Move it to the DU
header (where it logically belongs) to move it from there.

openair2/RRC/NR/rrc_gNB.c

@@ -112,16 +112,6 @@ extern RAN_CONTEXT_t RC;
 
 mui_t rrc_gNB_mui = 0;
 
-// the assoc_id might be 0 (if the DU goes offline). Below helper macro to
-// print an error and return from the function in that case
-#define RETURN_IF_INVALID_ASSOC_ID(assoc_id)                               \
-  {                                                                        \
-    if (assoc_id == 0) {                                                   \
-      LOG_E(NR_RRC, "cannot send data: invalid assoc_id 0, DU offline\n"); \
-      return;                                                              \
-    }                                                                      \
-  }
-
 ///---------------------------------------------------------------------------------------------------------------///
 ///---------------------------------------------------------------------------------------------------------------///
 

openair2/RRC/NR/rrc_gNB_du.h

@@ -48,4 +48,14 @@ int get_dl_band(const struct f1ap_served_cell_info_t *cell_info);
 int get_ssb_scs(const struct f1ap_served_cell_info_t *cell_info);
 int get_ssb_arfcn(const struct nr_rrc_du_container_t *du);
 
+// the assoc_id might be 0 (if the DU goes offline). Below helper macro to
+// print an error and return from the function in that case
+#define RETURN_IF_INVALID_ASSOC_ID(assoc_id)                               \
+  {                                                                        \
+    if (assoc_id == 0) {                                                   \
+      LOG_E(NR_RRC, "cannot send data: invalid assoc_id 0, DU offline\n"); \
+      return;                                                              \
+    }                                                                      \
+  }
+
 #endif /* RRC_GNB_DU_H_ */