staging: rtl8188eu: remove unused variables from core/rtw_mlme_ext.c

Remove set but unused variables from within the file core/rtw_mlme_ext.c,
as they are triggering kernel test robot warnings.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/r/20210615223607.13863-5-phil@philpotter.co.uk


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