mac80211: drop spelling fix

This is a partial revert of 42b2aa86 ("treewide: Fix typos in
various parts of the kernel, and fix some comments") as the code
has been refactored in the wireless tree.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>