net: stmmac: move gmac4 specific phylink capabilities to gmac4

Move the setup of gmac4 speicifc phylink capabilities into gmac4 code.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/E1qZAXY-005pUJ-Ez@rmk-PC.armlinux.org.uk


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