bnx2x: prevent CFC attention

During VF load, prior to sending messages on HW channel to PF the VF
checks its bulletin board to see whether the PF indicated it has closed;
If a closed PF is encountered, the VF skips sending the message.

Due to incorrect return values, there's a possible scenario in which the VF
finishes loading "successfully", while the PF hasn't actually fully configured
FW/HW for the VFs supposed configuration.
Once VF tries to send Tx packets, HW will raise an attention (and FW possibly
will start treat the VF as malicious).

The patch fails the loading process in such a scenario.
Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnx2x/bnx2x_vfpf.c

@@ -152,7 +152,7 @@ static int bnx2x_send_msg2pf(struct bnx2x *bp, u8 *done, dma_addr_t msg_mapping)
 	if (bp->old_bulletin.valid_bitmap & 1 << CHANNEL_DOWN) {
 		DP(BNX2X_MSG_IOV, "detecting channel down. Aborting message\n");
 		*done = PFVF_STATUS_SUCCESS;
-		return 0;
+		return -EINVAL;
 	}
 
 	/* Write message address */