staging: r8188eu: fix duplicated inclusion

Generated by: scripts/checkincludes.pl

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/r/20210731121843.GA54722@fdce12c5ae77


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