staging: xillybus: Removed write memory barriers before wait_event_*()

According to Documentation/memory-barriers.txt, a memory barrier is put
in place by wait_event_*()

Signed-off-by: Eli Billauer <eli.billauer@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --cc drivers/staging/xillybus/xillybus_core.c
Simple merge