rt2x00: Change RF3853 to RF3053.

According to the latest Ralink vendor drivers, this seems to be the real
RF chipset type.

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>