[PATCH] softmac: alloc_ieee80211() NULL check

This patch adds missing NULL check and trims a line longer than 80 columns.

Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Joe Jezak <josejx@gentoo.org>
Cc: Daniel Drake <dsd@gentoo.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>