staging: et131x: Remove PHY interrupt handling code from driver isr handler

The PHY interrupt is now handled by the phy_device, and the equivalent code is present in et131x_adjust_link, called from the phy_device when needed.

Signed-off-by: Mark Einon <mark.einon@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>