net: phylink: add debug for phylink_major_config()

Now that we have a more complexity in phylink_major_config(), augment
the debugging so we can see what's going on there.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1tIUrZ-006ITt-Fa@rmk-PC.armlinux.org.uk


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