util-lib: move shall_restore_state() to shared/reboot-util

It's just a small function, but it is higher-level functionality.
I don't see a good place for it, reboot-util.[ch] seems least bad

src/backlight/backlight.c

@@ -13,7 +13,7 @@
 #include "main-func.h"
 #include "mkdir.h"
 #include "parse-util.h"
-#include "proc-cmdline.h"
+#include "reboot-util.h"
 #include "string-util.h"
 #include "strv.h"
 #include "util.h"

src/basic/proc-cmdline.c

@@ -306,14 +306,3 @@ int proc_cmdline_get_key_many_internal(ProcCmdlineFlags flags, ...) {
 
         return ret;
 }
-
-int shall_restore_state(void) {
-        bool ret;
-        int r;
-
-        r = proc_cmdline_get_bool("systemd.restore_state", &ret);
-        if (r < 0)
-                return r;
-
-        return r > 0 ? ret : true;
-}

src/basic/proc-cmdline.h

@@ -27,8 +27,6 @@ int proc_cmdline_get_key_many_internal(ProcCmdlineFlags flags, ...);
 char *proc_cmdline_key_startswith(const char *s, const char *prefix);
 bool proc_cmdline_key_streq(const char *x, const char *y);
 
-int shall_restore_state(void);
-
 /* A little helper call, to be used in proc_cmdline_parse_t callbacks */
 static inline bool proc_cmdline_value_missing(const char *key, const char *value) {
         if (!value) {

src/rfkill/rfkill.c

@@ -16,15 +16,15 @@
 #include "fd-util.h"
 #include "fileio.h"
 #include "io-util.h"
+#include "list.h"
 #include "main-func.h"
 #include "mkdir.h"
 #include "parse-util.h"
-#include "proc-cmdline.h"
+#include "reboot-util.h"
 #include "string-table.h"
 #include "string-util.h"
 #include "udev-util.h"
 #include "util.h"
-#include "list.h"
 
 /* Note that any write is delayed until exit and the rfkill state will not be
  * stored for rfkill indices that disappear after a change. */

src/shared/reboot-util.c

@@ -6,6 +6,7 @@
 #include "alloc-util.h"
 #include "fileio.h"
 #include "log.h"
+#include "proc-cmdline.h"
 #include "raw-reboot.h"
 #include "reboot-util.h"
 #include "string-util.h"
@@ -96,3 +97,14 @@ int reboot_with_parameter(RebootFlags flags) {
 
         return log_full_errno(flags & REBOOT_LOG ? LOG_ERR : LOG_DEBUG, errno, "Failed to reboot: %m");
 }
+
+int shall_restore_state(void) {
+        bool ret;
+        int r;
+
+        r = proc_cmdline_get_bool("systemd.restore_state", &ret);
+        if (r < 0)
+                return r;
+
+        return r > 0 ? ret : true;
+}

src/shared/reboot-util.h

@@ -11,3 +11,5 @@ typedef enum RebootFlags {
 
 int read_reboot_parameter(char **parameter);
 int reboot_with_parameter(RebootFlags flags);
+
+int shall_restore_state(void);