mac80211: fix IBSS code

This patch fixes two errors introduced by

    commit 19d35612f3cd7f60dd9174c0100584e21f5a1025
    Author: Bruno Randolf <bruno@thinktube.com>
    Date:   Mon Feb 18 11:21:36 2008 +0900

        mac80211: enable IBSS merging

The first error is an endianness problem that sparse found and
the second is a build failure when CONFIG_MAC80211_IBSS_DEBUG
is not set.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Bruno Randolf <bruno@thinktube.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>