ethtool: Update to 4.17

ethtool: Update to 4.17

Tested on 8devices Jalapeno(ipq40xx)
Introduces following changes
* Fix: In ethtool.8, remove superfluous and incorrect \
* Fix: fix uninitialized return value
* Fix: fix RING_VF assignment
* Fix: remove unused global variable
* Fix: several fixes in do_gregs()
* Fix: correctly free hkey when get_stringset() fails
* Fix: remove unreachable code
* Fix: fix stack clash in do_get_phy_tunable and do_set_phy_tunable
* Feature: Add register dump support for MICROCHIP LAN78xx

Signed-off-by: Robert Marko <robimarko@gmail.com>