nl80211: moving comment line

The comment line before __NL80211_ATTR_AFTER_LAST should be put back
to where it was. Moving of the comment line was a typo introduced in
an earlier change.

Change-Id: I8e7a33132da77f71320b76f09559a596eb82cede
Signed-off-by: Xun Luo <sherwoodluo@codeaurora.org>