MIPS: Octeon: False positive timeout

If we reach the test just below the loop with a `timeout' value of 0,
this does not mean that the timeout caused the loop to end, but rather
the `smi_rd.s.pending', in the last iteration. If timeout caused the
loop to end, then `timeout' is -1, not 0.

Since this can occur only in the last iteration, it is not very likely
to be a problem. By changing the post- to prefix decrement we ensure
that a timeout of 0 does mean it timed out.
Signed-off-by: NRoel Kluin <roel.kluin@gmail.com>
Acked-by: NDavid Daney <ddaney@caviumnetworks.com>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

drivers/staging/octeon/cvmx-mdio.h

@@ -421,7 +421,7 @@ static inline int cvmx_mdio_45_read(int bus_id, int phy_id, int device,
 	do {
 		cvmx_wait(1000);
 		smi_rd.u64 = cvmx_read_csr(CVMX_SMIX_RD_DAT(bus_id));
-	} while (smi_rd.s.pending && timeout--);
+	} while (smi_rd.s.pending && --timeout);
 
 	if (timeout <= 0) {
 		cvmx_dprintf("cvmx_mdio_45_read: bus_id %d phy_id %2d "