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>