rt2x00: Make rt2800_init_led static and don't export it.

It is only used within the rt2800lib module itself.

Signed-off-by: Gertjan van Wingerde <gwingerde@gmail.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>