[PATCH] fix profiling

[Brian Dessent]

Brian Dessent wrote:

> Since this code is lifted from the BSDs I did check that this change was
> made there as well, e.g.
> <http://www.openbsd.org/cgi-bin/cvsweb/src/sys/arch/i386/include/profile.h?rev=1.10&content-type=text/x-cvsweb-markup>.

Actually, I also missed that the above version uses +r instead of =r for
the second constraint.  I guess we should make that change too.

Brian