[CASSINI]: Check pci_set_mwi() return value.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/cassini.c b/drivers/net/cassini.c
index 4aec747..9fe3a38 100644
--- a/drivers/net/cassini.c
+++ b/drivers/net/cassini.c
@@ -4919,7 +4919,10 @@
 	pci_cmd &= ~PCI_COMMAND_SERR;
 	pci_cmd |= PCI_COMMAND_PARITY;
 	pci_write_config_word(pdev, PCI_COMMAND, pci_cmd);
-	pci_set_mwi(pdev);
+	if (pci_set_mwi(pdev))
+		printk(KERN_WARNING PFX "Could enable MWI for %s\n",
+		       pci_name(pdev));
+
 	/*
 	 * On some architectures, the default cache line size set
 	 * by pci_set_mwi reduces perforamnce.  We have to increase