Rename 'bts_data' leftovers to 'bts'

Before, we used tho have a BTs object split into 2 parts, a C
gprs_rlcmac_bts struct and a C++ BTS struct, and "bts_data" naming was
used to distinguish them in variable names. Nowadays the struct is
finally combined into one, so there's no point in using this "bts_data"
terminology, we use always "bts".

Change-Id: I9852bf439292d1abc70711bea65698b21bde0ee8
diff --git a/src/tbf.h b/src/tbf.h
index cb4c9b9..73266bf 100644
--- a/src/tbf.h
+++ b/src/tbf.h
@@ -348,7 +348,6 @@
 	struct llist_item m_bts_list;
 
 protected:
-	gprs_rlcmac_bts *bts_data() const;
 	void merge_and_clear_ms(GprsMs *old_ms);
 
 	gprs_llc_queue *llc_queue();
@@ -567,6 +566,6 @@
 		((int)GPRS_RLCMAC_UL_TBF - (int)dir + (int)GPRS_RLCMAC_DL_TBF);
 }
 
-uint16_t egprs_window_size(const struct gprs_rlcmac_bts *bts_data, uint8_t slots);
+uint16_t egprs_window_size(const struct gprs_rlcmac_bts *bts, uint8_t slots);
 
 #endif