net: stmmac: rk: convert to suspend()/resume() methods

net: stmmac: rk: convert to suspend()/resume() methods

Convert rk to use the new suspend() and resume() methods rather than
implementing these in custom wrappers around the main driver's
suspend/resume methods. This allows this driver to use the simmac
simple PM ops structure.

We can further simplify the driver as there is no need to track whether
the device was suspended, we only need to check whether the device is
wakeup capable in the resume method. This is because the resume method
will only be called after the suspend method.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1ulXc2-008grB-9k@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>