staging: r8188eu: brfoffbyhw is always false

As a consequence of the bHWPwrPindetect removal, brfoffbyhw is never set
to true any more. Remove the variable and code that depends on
brfoffbyhw == true.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20210918135722.23976-1-martin@kaiser.cx


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