ipa: rename `struct ipa_link' by `struct ipa_client_link'

And IPA_LINK_STATE_* by IPA_CLIENT_LINK_STATE_* to prepare
the addition of the ipa_server_link abstraction.
diff --git a/include/osmocom/abis/ipa.h b/include/osmocom/abis/ipa.h
index 69888f5..bba7e8f 100644
--- a/include/osmocom/abis/ipa.h
+++ b/include/osmocom/abis/ipa.h
@@ -5,29 +5,29 @@
 #include <osmocom/core/linuxlist.h>
 #include <osmocom/core/timer.h>
 
-enum ipa_link_state {
-	IPA_LINK_STATE_NONE         = 0,
-	IPA_LINK_STATE_CONNECTING   = 1,
-	IPA_LINK_STATE_CONNECTED    = 2,
-	IPA_LINK_STATE_MAX
+enum ipa_client_link_state {
+	IPA_CLIENT_LINK_STATE_NONE         = 0,
+	IPA_CLIENT_LINK_STATE_CONNECTING   = 1,
+	IPA_CLIENT_LINK_STATE_CONNECTED    = 2,
+	IPA_CLIENT_LINK_STATE_MAX
 };
 
-struct ipa_link {
-	struct e1inp_line	*line;
-	struct osmo_fd		ofd;
-	struct llist_head	tx_queue;
-	struct osmo_timer_list	timer;
-	enum ipa_link_state	state;
-	const char		*addr;
-	uint16_t		port;
-	int (*cb)(struct ipa_link *link, struct msgb *msg);
+struct ipa_client_link {
+	struct e1inp_line		*line;
+	struct osmo_fd			ofd;
+	struct llist_head		tx_queue;
+	struct osmo_timer_list		timer;
+	enum ipa_client_link_state	state;
+	const char			*addr;
+	uint16_t			port;
+	int (*cb)(struct ipa_client_link *link, struct msgb *msg);
 };
 
-struct ipa_link *ipa_client_link_create(void *ctx, struct e1inp_line *line, const char *addr, uint16_t port, int (*cb)(struct ipa_link *link, struct msgb *msgb));
-void ipa_client_link_destroy(struct ipa_link *link);
+struct ipa_client_link *ipa_client_link_create(void *ctx, struct e1inp_line *line, const char *addr, uint16_t port, int (*cb)(struct ipa_client_link *link, struct msgb *msgb));
+void ipa_client_link_destroy(struct ipa_client_link *link);
 
-int ipa_client_link_open(struct ipa_link *link);
-void ipa_client_link_close(struct ipa_link *link);
+int ipa_client_link_open(struct ipa_client_link *link);
+void ipa_client_link_close(struct ipa_client_link *link);
 
 int ipa_msg_recv(int fd, struct msgb **rmsg);