Split identity_lv param into mi+mi_len

It's not really needed to have those together in some function calls,
and makes it more difficult to follow the code. Furthermore, new callers
not having content already aligned (len+value) will be using these
functions in forthcoming commits.

Change-Id: Ifb9d3997bfb74b35366c3d1bc51ce458f19abf16
diff --git a/src/bts.h b/src/bts.h
index 7ef5a3f..0eaab85 100644
--- a/src/bts.h
+++ b/src/bts.h
@@ -290,7 +290,7 @@
 	int current_frame_number() const;
 
 	/** add paging to paging queue(s) */
-	int add_paging(uint8_t chan_needed, uint8_t *identity_lv);
+	int add_paging(uint8_t chan_needed, const uint8_t *mi, uint8_t mi_len);
 
 	gprs_rlcmac_dl_tbf *dl_tbf_by_poll_fn(uint32_t fn, uint8_t trx, uint8_t ts);
 	gprs_rlcmac_ul_tbf *ul_tbf_by_poll_fn(uint32_t fn, uint8_t trx, uint8_t ts);