logind: make session_prepare_vt() static

src/login/logind-session.c

@@ -1183,7 +1183,7 @@ static int session_open_vt(Session *s) {
         return s->vtfd;
 }
 
-int session_prepare_vt(Session *s) {
+static int session_prepare_vt(Session *s) {
         int vt, r;
         struct vt_mode mode = {};
 

src/login/logind-session.h

@@ -161,7 +161,6 @@ KillWho kill_who_from_string(const char *s) _pure_;
 const char* tty_validity_to_string(TTYValidity t) _const_;
 TTYValidity tty_validity_from_string(const char *s) _pure_;
 
-int session_prepare_vt(Session *s);
 void session_leave_vt(Session *s);
 
 bool session_is_controller(Session *s, const char *sender);