staging: r8188eu: remove HW_VAR_RESP_SIFS from SetHwReg8188EU()

SetHwReg8188EU() is called with HW_VAR_RESP_SIFS only in one place.
Remove the HW_VAR_RESP_SIFS case from SetHwReg8188EU() and call
rtw_write8() directly instead. This is part of the ongoing effort to
get rid of the unwanted hal layer.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20220329202141.7028-2-straube.linux@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>