net: phy: c45: add support for 1000BASE-T1 forced setup

commit 01f5f26c116ca762d336f01443f334db465fdfb1 from
https://github.com/nxp-auto-linux/linux



Add support to force 1000BASE-T1 by setting the correct control bit in
the MDIO_MMD_PMA_PMD_BT1_CTRL register.

Issue: ALB-10440

Signed-off-by: Stefan Eichenberger <eichest@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
(cherry picked from commit 25108a83)
Signed-off-by: Zhantao Tang <zhantao.tang@windriver.com>