liquidio: CN23XX: fix a loop timeout

This is supposed to loop 1000 times and then give up.  The problem is
it's a post-op and after the loop we test if "loop" is zero when really
it would be -1.  Fix this by making it a pre-op.

Fixes: 1b7c55c4538b ("liquidio: CN23XX queue manipulation")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/cavium/liquidio/cn23xx_pf_device.c b/drivers/net/ethernet/cavium/liquidio/cn23xx_pf_device.c
index bddb198..380a641 100644
--- a/drivers/net/ethernet/cavium/liquidio/cn23xx_pf_device.c
+++ b/drivers/net/ethernet/cavium/liquidio/cn23xx_pf_device.c
@@ -693,7 +693,7 @@
 				while ((reg_val & CN23XX_PKT_INPUT_CTL_RST) &&
 				       !(reg_val &
 					 CN23XX_PKT_INPUT_CTL_QUIET) &&
-				       loop--) {
+				       --loop) {
 					reg_val = octeon_read_csr64(
 					    oct,
 					    CN23XX_SLI_IQ_PKT_CONTROL64(q_no));