[PATCH] USB: ipw.c driver fix

The below patch fixes the ipw module in kernel 2.6.17 for me; without
this change it simply does not work at all (all but the first writes are
refused because write_urb_busy is always 1).

This problem was there in 2.6.15 as well, but at that point I used the
(updated) ipw.c, version 0.4, from
http://www.neology.co.za/products/opensource/ipwireless/

 which no longer
compiles with 2.6.17. It can be made to after a few changes but
obviously it's easier if the built-in ipw driver works instead of having
to download one from the neology site.

From: Bart Oldeman <bartoldeman@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>