pdch: Simplify the reset code, rename variables to XYZ_no

Simplify the reset code now that the PDCH can know where it is
located. Rename the variables in the sba to trx_no and ts_no as
it stores the number and not the actual thing.
diff --git a/src/bts.h b/src/bts.h
index c05779a..a8b6223 100644
--- a/src/bts.h
+++ b/src/bts.h
@@ -47,8 +47,7 @@
 
 	void add_paging(struct gprs_rlcmac_paging *pag);
 
-	/* TODO: the PDCH should know the trx/ts it belongs to */
-	void free_resources(BTS *bts, uint8_t trx, uint8_t ts);
+	void free_resources();
 
 	bool is_enabled() const;