BACKPORT: net: phy: Allow drivers to always call into ->suspend()

A few PHY drivers are currently attempting to not suspend the PHY when
Wake-on-LAN is enabled, however that code is not currently executing at
all due to an early check in phy_suspend().

This prevents PHY drivers from making an appropriate decisions and put
the hardware into a low power state if desired.

In order to allow the PHY drivers to opt into getting their ->suspend
routine to be called, add a PHY_ALWAYS_CALL_SUSPEND bit which can be
set. A boolean that tracks whether the PHY or the attached MAC has
Wake-on-LAN enabled is also provided for convenience.

If phydev::wol_enabled then the PHY shall not prevent its own
Wake-on-LAN detection logic from working and shall not prevent the
Ethernet MAC from receiving packets for matching.

Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Change-Id: I9077fe16d2515b60a2cb58753e6914be95a6923a
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit a7e34480)
[danesh: Moved phydev->wol_enabled to avoid KMI-break]
Signed-off-by: Danesh Petigara <danesh.petigara@broadcom.com>