tg3: Fix return ring size breakage

Commit f6eb9b1fc1411d22c073f5264e5630a541d0f7df, "tg3: Add 5717 asic
rev" changed how the rx return ring size operations are done.  It
effectively inverts the sense of the previous test, but it failed to
also invert the resulting sizes.  This patch corrects that error.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed