Increase the SmartEEE Tw parameter for Atheros PHYs to stop gigabit
links from sporadically dropping. Testing on this platform shows that
a value of 24 results in a stable link, whereas 23 or below has the
occasional drop.
Tested with a Netgear GS116 unmanaged switch link partner with Cat 5e
cabling.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Shawn Guo <shawnguo@kernel.org>