smsc911x: No need to print driver version

Having the kernel to print:

"smsc911x: Driver version 2008-10-21" on every boot is not very useful, so
remove the print of the driver version.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>