mac80211: Fix IBSS merge

Currently, in IBSS mode, a single creator would go into
a loop trying to merge/scan. This happens because the IBSS timer is
rearmed on finishing a scan and the subsequent
timer invocation requests another scan immediately.

This patch fixes this issue by checking if we have just completed
a scan run trying to merge with other IBSS networks.

Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>