phylib: do EXPORT_SYMBOL on get_phy_id

Commit cac1f3c8 factored out the code for get_phy_id so that it
could be reused in multiple places.  Turns out that some of the
users can be modular, so we need to export this symbol as well.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/net/phy/phy_device.c

@@ -207,6 +207,7 @@ int get_phy_id(struct mii_bus *bus, int addr, u32 *phy_id)
 
 	return 0;
 }
+EXPORT_SYMBOL(get_phy_id);
 
 /**
  * get_phy_device - reads the specified PHY device and returns its @phy_device struct