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: 2f664823 ("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>