rtl8192u: remove space between function name and '(' in r8192U_core.c

This patch fixes the following checkpatch warning:
WARNING: space prohibited between function name and
open parenthesis '('

Signed-off-by: Xenia Ragiadakou <burzalodowa@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>