staging: rtl8188eu: remove unused parameter of HalSetBrateCfg()

The parameter 'struct adapter *adapt' of HalSetBrateCfg() is unused,
so remove it.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>