msc_a,vlr: rename ciphering_required to try_ciphering

Clarify the name to avoid confusion in upcoming patches.

This function actually returns whether any ciphering mode besides A5/0
is enabled, and does not imply that ciphering is mandatory. A5/0 may
well be allowed when this function returns true.

Related: OS#4830
Change-Id: Ia55085e3b36feb275bcf92fc91a4be7d1c24a6b9
diff --git a/include/osmocom/msc/vlr.h b/include/osmocom/msc/vlr.h
index d23661d..db9c72b 100644
--- a/include/osmocom/msc/vlr.h
+++ b/include/osmocom/msc/vlr.h
@@ -299,7 +299,7 @@
 	       const struct osmo_location_area_id *old_lai,
 	       const struct osmo_location_area_id *new_lai,
 	       bool authentication_required,
-	       bool ciphering_required,
+	       bool try_ciphering,
 	       uint8_t key_seq,
 	       bool is_r99, bool is_utran,
 	       bool assign_tmsi);
@@ -463,7 +463,7 @@
 		 const struct osmo_mobile_identity *mi,
 		 const struct osmo_location_area_id *lai,
 		 bool authentication_required,
-		 bool ciphering_required,
+		 bool try_ciphering,
 		 uint8_t key_seq,
 		 bool is_r99, bool is_utran);