MACCSR2
reg = rt2x00mmio_register_read(rt2x00dev, MACCSR2);
rt2x00mmio_register_write(rt2x00dev, MACCSR2, reg);
rt2x00mmio_register_write(rt2x00dev, MACCSR2, reg);
reg = rt2x00mmio_register_read(rt2x00dev, MACCSR2);