phy: atheros: ar8035: Fix clock output calculation

The clock ouput frequency is calculated incorrectly for AR8035 due to
wrong masking of priv->clk_25m_reg and priv->clk_25m_mask.

This same issue has been already fixed in the kernel by:

commit b1f4c209d84057b6d40b939b6e4404854271d797
Author: Oleksij Rempel <o.rempel@pengutronix.de>
Date:   Wed Apr 1 11:57:32 2020 +0200

    net: phy: at803x: fix clock sink configuration on ATH8030 and ATH8035

    The masks in priv->clk_25m_reg and priv->clk_25m_mask are one-bits-set
    for the values that comprise the fields, not zero-bits-set.

    This patch fixes the clock frequency configuration for ATH8030 and
    ATH8035 Atheros PHYs by removing the erroneous "~".

    To reproduce this bug, configure the PHY  with the device tree binding
    "qca,clk-out-frequency" and remove the machine specific PHY fixups.

    Fixes: 2f664823a47021 ("net: phy: at803x: add device tree binding")
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reported-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Russell King <rmk+kernel@armlinux.org.uk>
Tested-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

Apply the same fix in the U-Boot driver.

Tested on a i.MX6 Hummingboard.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Michael Walle <michael@walle.cc>
Tested-by: Tom Rini <trini@konsulko.com>