This loop ends with count set to -1 and not zero so the warning message
isn't printed when it should be.  I've fixed this by change the postop
to a preop.

Fixes: 0990822c ('VFIO: platform: reset: AMD xgbe reset module')
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NEric Auger <eric.auger@linaro.org>
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>