Documentation/networking/wavelan.txt: deleted, not in tree

Commit 1d794e3b ("Staging: wavelan: delete the driver") removed the
source, so remove the documentation as well.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Jean Tourrilhes <jt@hpl.hp.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>