Revert "net: phy: microchip: force IRQ polling mode for lan88xx"

This reverts commit 9b89102f which is
commit 30a41ed3 upstream.

It is reported to cause NFS boot problems on a Raspberry Pi 3b so revert
it from this branch for now.

Cc: Fiona Klute <fiona.klute@gmx.de>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Sasha Levin <sashal@kernel.org>
Link: https://lore.kernel.org/r/aB6uurX99AZWM9I1@finisterre.sirena.org.uk


Reported-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>