rtl8192u: remove whitespace after '(' and before ')' in r8192U.h

This patch fixes the following checkpatch errors:
ERROR: space prohibited after that open parenthesis '('
ERROR: space prohibited before that close parenthesis ')'

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