net: stmmac: rename xpcs_an_inband to default_an_inband

Rename xpcs_an_inband to default_an_inband to reflect the change in
phylink and its changed functionality.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Halaney <ahalaney@redhat.com>
Link: https://lore.kernel.org/r/E1sCJN6-00EcrD-43@rmk-PC.armlinux.org.uk


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