net: phylink: move MLO_AN_PHY resolve handling to if() statement

The switch() statement doesn't sit very well with the preceeding if()
statements, and results in excessive indentation that spoils code
readability. Continue cleaning this up by converting the MLO_AN_PHY
case to use an if() statmeent.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1t9RQp-002Fet-5W@rmk-PC.armlinux.org.uk


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