add LOG_RAN_CONN() to use the conn->fi->id for context

For each conn, set a default logging category, to distinguish categories for
BSSMAP and RANAP based conns.

LOG_RAN_CONN(): log with the conn's default category,

LOG_RAN_CONN_CAT(): log with a manually set category (mostly for keeping
previous DMM logging on the same category).

In some places, replace LOGP() using manual context with LOG_RAN_CONN(), and
remove the manual context info, now provided by the conn->fi->id.

This is loosely related to inter-BSC and inter-MSC handover: to speed up
refactoring, I want to avoid the need for manual logging context and just use
this LOG_RAN_CONN().

Change-Id: I0a7809840428b1e028df6eb683bc5ffcc8df474a
diff --git a/src/libmsc/a_iface_bssap.c b/src/libmsc/a_iface_bssap.c
index 491f8d0..41af93c 100644
--- a/src/libmsc/a_iface_bssap.c
+++ b/src/libmsc/a_iface_bssap.c
@@ -35,11 +35,14 @@
 #include <osmocom/msc/a_reset.h>
 #include <osmocom/msc/transaction.h>
 #include <osmocom/msc/msc_mgcp.h>
+#include <osmocom/msc/ran_conn.h>
 
 #include <errno.h>
 
 #define IP_V4_ADDR_LEN 4
 
+#define LOGPCONN LOG_RAN_CONN
+
 /*
  * Helper functions to lookup and allocate subscribers
  */