chan_alloc: Print bts nr on chan alloc failure

Also change format of related debug message to match similar format than
gsm_ts_and_pchan_name().

Change-Id: Id4f875944c40fd862fc63feec82216c45d2e41c2
diff --git a/src/libbsc/chan_alloc.c b/src/libbsc/chan_alloc.c
index d773382..4eccff0 100644
--- a/src/libbsc/chan_alloc.c
+++ b/src/libbsc/chan_alloc.c
@@ -338,7 +338,7 @@
 	struct gsm_lchan *lchan = NULL;
 	enum gsm_phys_chan_config first, first_cbch, second, second_cbch;
 
-	LOGP(DRLL, LOGL_DEBUG, "bts-%d lchan_alloc(%s)\n", bts->nr, gsm_lchant_name(type));
+	LOGP(DRLL, LOGL_DEBUG, "(bts=%d) lchan_alloc(%s)\n", bts->nr, gsm_lchant_name(type));
 
 	switch (type) {
 	case GSM_LCHAN_SDCCH:
@@ -488,8 +488,8 @@
 	} else {
 		struct challoc_signal_data sig;
 
-		LOGP(DRLL, LOGL_ERROR, "Failed to allocate %s channel\n",
-		     gsm_lchant_name(type));
+		LOGP(DRLL, LOGL_ERROR, "(bts=%d) Failed to allocate %s channel\n",
+		     bts->nr, gsm_lchant_name(type));
 
 		sig.bts = bts;
 		sig.type = type;