staging: r8188eu: setting HW_VAR_SET_RPWM does nothing

Setting the HW_VAR_SET_RPWM "hardware variable" is an empty operation.

Remove the call to set HW_VAR_SET_RPWM, the calculation of the value to be
set and the definition of HW_VAR_SET_RPWM itself.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20210911141521.24901-3-martin@kaiser.cx


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