Move ws_* fields from BTS to PCU

Change-Id: I997bc52f0d924c8f2a0b1d6cf23af98828ad4258
diff --git a/src/tbf.cpp b/src/tbf.cpp
index eb043e5..43c8cbf 100644
--- a/src/tbf.cpp
+++ b/src/tbf.cpp
@@ -321,7 +321,7 @@
 	uint8_t num_pdch = pcu_bitcount(slots);
 
 	return OSMO_MIN((num_pdch != 1) ? (128 * num_pdch) : 192,
-			OSMO_MAX(64, (bts_data->ws_base + num_pdch * bts_data->ws_pdch) / 32 * 32));
+			OSMO_MAX(64, (the_pcu->vty.ws_base + num_pdch * the_pcu->vty.ws_pdch) / 32 * 32));
 }
 
 int gprs_rlcmac_tbf::update()