Bluetooth: Audio: CSIP set coordinator API not using bt_csip

Modified the CSIP set coordinator slightly to not use the
bt_csip struct at all. For the use a void pointer works
equally well.

Signed-off-by: Emil Gydesen <emil.gydesen@nordicsemi.no>
diff --git a/include/zephyr/bluetooth/audio/csip.h b/include/zephyr/bluetooth/audio/csip.h
index 8e5aad6..3a5bff4 100644
--- a/include/zephyr/bluetooth/audio/csip.h
+++ b/include/zephyr/bluetooth/audio/csip.h
@@ -251,7 +251,7 @@
 	struct bt_csip_set_coordinator_set_info info;
 
 	/** Internally used pointer value */
-	struct bt_csip *csip;
+	void *svc_inst;
 };
 
 /** Struct representing a remote device as a set member */
diff --git a/subsys/bluetooth/audio/csip_set_coordinator.c b/subsys/bluetooth/audio/csip_set_coordinator.c
index 9d0d2a7..1c3ecd9 100644
--- a/subsys/bluetooth/audio/csip_set_coordinator.c
+++ b/subsys/bluetooth/audio/csip_set_coordinator.c
@@ -622,7 +622,7 @@
 	int err;
 
 	/* Start reading values and call CB when done */
-	err = read_set_sirk(member->insts[0].csip);
+	err = read_set_sirk((struct bt_csip *)member->insts[0].svc_inst);
 	if (err == 0) {
 		busy = true;
 	}
@@ -1397,7 +1397,7 @@
 	err = bt_gatt_discover(conn, &discover_params);
 	if (err == 0) {
 		for (size_t i = 0; i < ARRAY_SIZE(client->set_member.insts); i++) {
-			client->set_member.insts[i].csip = &client->csip_insts[i];
+			client->set_member.insts[i].svc_inst = (void *)&client->csip_insts[i];
 		}
 		busy = true;
 		client->conn = bt_conn_ref(conn);