drivers/net/tokenring/olympic.c: fix warning

When dev_name() is changed to return `const char *':

drivers/net/tokenring/olympic.c: In function 'olympic_probe':
drivers/net/tokenring/olympic.c:234: warning: assignment discards qualifiers from pointer target type

Cc: Jeff Garzik <jeff@garzik.org>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/net/tokenring/olympic.h

@@ -254,7 +254,7 @@ struct olympic_private {
 	u8 __iomem *olympic_mmio;
 	u8 __iomem *olympic_lap;
 	struct pci_dev *pdev ; 
-	char *olympic_card_name ; 
+	const char *olympic_card_name;
 
 	spinlock_t olympic_lock ;