Staging: dst: Fix parentheses

`|' has a higher precedence than `?' so since MSG_WAITALL is
defined 0x100, MSG_MORE was always written to the msg_flag.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>