net: phy: atheros: Fix the masks for AR8031/8035

Use the same masks as used in the kernel:
https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/drivers/net/phy/at803x.c?id=refs/tags/v3.12.6



With such changes Ethernet is functional on hummingboard solo.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Stefano Babic <sbabic@denx.de>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Acked-by: Marek Vasut <marex@denx.de>
Patch: 306640