The current code retrieves the firmware package version from firmware
everytime ethtool -i is run.  There is no reason to do that as the
firmware will not change while the driver is loaded.  Get the version
once at init time.

Also, display the full 4-part firmware version string and remove the
less useful interface spec version.
Signed-off-by: NMichael Chan <michael.chan@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>