staging: r8188eu: remove rtw_hw_suspend

The bHWPwrPindetect cleanup removed the only call to rtw_hw_suspend.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20210911161019.26881-4-martin@kaiser.cx


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