vt: Fix build breakage when !CONFIG_VT_CONSOLE

Commit 68952076 ("vt: Remove
vt_get_kmsg_redirect() from uapi header") fails to compile if
!CONFIG_VT_CONSOLE.

Move macro definition for vt_get_kmsg_redirect() up with file-scope
function declarations.
Reported-by: NJim Davis <jim.epost@gmail.com>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/vt/vt.c

@@ -156,6 +156,8 @@ static void console_callback(struct work_struct *ignored);
 static void blank_screen_t(unsigned long dummy);
 static void set_palette(struct vc_data *vc);
 
+#define vt_get_kmsg_redirect() vt_kmsg_redirect(-1)
+
 static int printable;		/* Is console ready for printing? */
 int default_utf8 = true;
 module_param(default_utf8, int, S_IRUGO | S_IWUSR);
@@ -2513,8 +2515,6 @@ int vt_kmsg_redirect(int new)
 		return kmsg_con;
 }
 
-#define vt_get_kmsg_redirect() vt_kmsg_redirect(-1)
-
 /*
  *	Console on virtual terminal
  *