b44: Truncate PHY address

Some ROMs on embedded devices store incorrect values for the PHY address of the ethernet device.
It looks like the number is sign-extended. Truncate the value by applying the PHY-address mask to it.

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This patch is untested and needs some testing before it can go upstream, but I think the chance of introducing bugs with this is almost zero, as the PHY address register really is only 5 bits long. So this will do The Right Thing (tm) in any case. Please report result of the testing back to me. I will also run some tests later and then submit the patch for inclusion.

Index: wireless-testing/drivers/net/b44.c
===================================================================
@@ -2082,6 +2082,11 @@ static int __devinit b44_get_invariants(
 		addr = sdev->bus->sprom.et0mac;
 		bp->phy_addr = sdev->bus->sprom.et0phyaddr;
 	}
+	/* Some ROMs have buggy PHY addresses with the high
+	 * bits set (sign extension?). Truncate them to a
+	 * valid PHY address. */
+	bp->phy_addr &= 0x1F;
+
 	memcpy(bp->dev->dev_addr, addr, 6);
 
 	if (!is_valid_ether_addr(&bp->dev->dev_addr[0])){

Greetings Michael.