put back 0x050d,0x7050 to rt73usb, same usb_id for two chips:

K7SF5D7050A ver 2xxx is rt2500
K7SF5D7050B ver 3xxx is rt73

<http://en-us-support.belkin.com/app/answers/detail/a_id/297/kw/K7SF5D7050>
Signed-off-by: NXose Vazquez Perez <xose.vazquez@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>