compat_ioctl: fix make headers_check regression

Fix headers_check error introduced by 390192b3:

include/linux/fd.h:6: included file 'linux/compat.h' is not exported

Signed-off-by: Johannes Stezenbach <js@sig21.net>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>