staging: rtl8188eu: Remove unused iw_operation_mode[]

Remove unused iw_operation_mode array.

Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Link: https://lore.kernel.org/r/20210721112829.17317-1-fmdefrancesco@gmail.com


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