Revert "madwifi: fix build against Linux 3.7"

This reverts commit fdabc38a090b74709b2aed90ab9bc7df07986768.

git-svn-id: svn://svn.openwrt.org/openwrt@36761 3c298f89-4303-0410-b956-a3cf2f4a3e73
madwifi: properly fix build against Linux 3.7 and later

git-svn-id: svn://svn.openwrt.org/openwrt@36762 3c298f89-4303-0410-b956-a3cf2f4a3e73