net: stmmac: imx: use phylink's interface mode for set_clk_tx_rate()

net: stmmac: imx: use phylink's interface mode for set_clk_tx_rate()

imx_dwmac_set_clk_tx_rate() is passed the interface mode from phylink
which will be the same as plat_dat->phy_interface. Use the passed-in
interface mode rather than plat_dat->phy_interface.

Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Tested-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1vFt4N-0000000ChoM-1llp@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>