The headers in drivers/net/wireless/rt2x00/rt2x00lib.h don't match the
use of the function in rt2x00dev.c The build fails as a result.
This has been a problem in linux-next since early September. I've
e-mailed a patch to linux-next and to linux-net, but the 2.6.32 merge
window has brought the problem to the mainline and so I'm re-sending
my patch. I've opened a bug on bugzilla:
http://bugzilla.kernel.org/show_bug.cgi?id=14217
Take care.
Ken