tbf: Fix typos in log messages concerning UL/DL

The TBF in create_dl_ass can be of any direction. The text in
rcv_resource_request uses DL instead of UL.

Sponsored-by: On-Waves ehf
diff --git a/src/tbf.cpp b/src/tbf.cpp
index c63d7cc..457fe24 100644
--- a/src/tbf.cpp
+++ b/src/tbf.cpp
@@ -737,7 +737,7 @@
 
 	if (!new_dl_tbf) {
 		LOGP(DRLCMACDL, LOGL_ERROR, "We have a schedule for downlink "
-			"assignment at uplink %s, but there is no downlink "
+			"assignment at %s, but there is no downlink "
 			"TBF\n", tbf_name(this));
 		dl_ass_state = GPRS_RLCMAC_DL_ASS_NONE;
 		return NULL;