net: stmmac: ingenic: convert to devm_stmmac_pltfr_probe()

As Ingenic now uses the stmmac platform PM ops, convert it to use
devm_stmmac_pltfr_probe() which will call the plat_dat->init() method
before stmmac_drv_probe() and appropriately cleaning up via the
->exit() method, thus simplifying the code. Using the devm_*()
variant also allows removal of the explicit call to
stmmac_pltfr_remove().

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/E1u4M5S-000YGJ-9K@rmk-PC.armlinux.org.uk


Signed-off-by: Jakub Kicinski <kuba@kernel.org>