[PATCH] rtl8187: fix endianness issue in rtl8225 register writing

I failed to notice that a u16 was being passed to the hardware.
This fixes it.

Thanks to Kasper F. Brandt for finding this!

Signed-off-by: Michael Wu <flamingice@sourmilk.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>