src: use namespace prefix osmo_fd* and osmo_select*

Summary of changes:

s/struct bsc_fd/struct osmo_fd/g
s/bsc_register_fd/osmo_fd_register/g
s/bsc_unregister_fd/osmo_fd_unregister/g
s/bsc_select_main/osmo_select_main/g
diff --git a/openbsc/src/gprs/gb_proxy_main.c b/openbsc/src/gprs/gb_proxy_main.c
index 4f6944f..b0fb664 100644
--- a/openbsc/src/gprs/gb_proxy_main.c
+++ b/openbsc/src/gprs/gb_proxy_main.c
@@ -279,7 +279,7 @@
 	gbprox_reset_persistent_nsvcs(bssgp_nsi);
 
 	while (1) {
-		rc = bsc_select_main(0);
+		rc = osmo_select_main(0);
 		if (rc < 0)
 			exit(3);
 	}
diff --git a/openbsc/src/gprs/sgsn_libgtp.c b/openbsc/src/gprs/sgsn_libgtp.c
index 7e66035..f193aa3 100644
--- a/openbsc/src/gprs/sgsn_libgtp.c
+++ b/openbsc/src/gprs/sgsn_libgtp.c
@@ -505,7 +505,7 @@
 }
 
 /* libgtp select loop integration */
-static int sgsn_gtp_fd_cb(struct bsc_fd *fd, unsigned int what)
+static int sgsn_gtp_fd_cb(struct osmo_fd *fd, unsigned int what)
 {
 	struct sgsn_instance *sgi = fd->data;
 	int rc;
@@ -570,7 +570,7 @@
 	sgi->gtp_fd0.data = sgi;
 	sgi->gtp_fd0.when = BSC_FD_READ;
 	sgi->gtp_fd0.cb = sgsn_gtp_fd_cb;
-	rc = bsc_register_fd(&sgi->gtp_fd0);
+	rc = osmo_fd_register(&sgi->gtp_fd0);
 	if (rc < 0)
 		return rc;
 
@@ -579,7 +579,7 @@
 	sgi->gtp_fd1c.data = sgi;
 	sgi->gtp_fd1c.when = BSC_FD_READ;
 	sgi->gtp_fd1c.cb = sgsn_gtp_fd_cb;
-	bsc_register_fd(&sgi->gtp_fd1c);
+	osmo_fd_register(&sgi->gtp_fd1c);
 	if (rc < 0)
 		return rc;
 
@@ -588,7 +588,7 @@
 	sgi->gtp_fd1u.data = sgi;
 	sgi->gtp_fd1u.when = BSC_FD_READ;
 	sgi->gtp_fd1u.cb = sgsn_gtp_fd_cb;
-	bsc_register_fd(&sgi->gtp_fd1u);
+	osmo_fd_register(&sgi->gtp_fd1u);
 	if (rc < 0)
 		return rc;
 
diff --git a/openbsc/src/gprs/sgsn_main.c b/openbsc/src/gprs/sgsn_main.c
index f6a645f..6876939 100644
--- a/openbsc/src/gprs/sgsn_main.c
+++ b/openbsc/src/gprs/sgsn_main.c
@@ -279,7 +279,7 @@
 	}
 
 	while (1) {
-		rc = bsc_select_main(0);
+		rc = osmo_select_main(0);
 		if (rc < 0)
 			exit(3);
 	}