staging: rtl8188eu: add missing blank lines after declarations

Fixes checkpatch warnings:
  WARNING: Missing a blank line after declarations

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Cc: Greg Kroah-Hartman <gregkh@linux.com>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>