net: ftgmac100: Simplify legacy MDIO setup

net: ftgmac100: Simplify legacy MDIO setup

There are old device trees which place the PHY nodes directly in the
MAC nodes, rather than within an MDIO container node.

The probe logic indicates that the use of NCSI and the legacy
placement of PHYs is mutually exclusive. Hence priv->use_ncsi cannot
be true, so there is no reason to set it false.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Jacky Chou <jacky_chou@aspeedtech.com>
Link: https://patch.msgid.link/20260206-ftgmac-cleanup-v5-10-ad28a9067ea7@aspeedtech.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>