Staging: document 4k stack problem for winbond driver

As noticed by Arjan

Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Pavel Machek <pavel@suse.cz>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/winbond/README

@@ -5,6 +5,7 @@ TODO:
 	- remove typedefs
 	- remove unused ioctls
 	- use cfg80211 for regulatory stuff
+	- fix 4k stack problems
 
 Please send patches to Greg Kroah-Hartman <greg@kroah.com> and
 Pavel Machek <pavel@suse.cz>