Associate PHY device with its device node specified by phy-handle
property. This makes it possible for PHY drivers to read dedicated
information to configure the PHY device.

Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>

In mtk_eth_of_to_plat, the last error check has the value in
'priv->phy_addr' but returns ret. Correct to return 'priv->phy_addr'
instead.

This issue was found by Smatch.

Signed-off-by: Andrew Goodbody <andrew.goodbody@linaro.org>

This patch adds support for MediaTek MT7987.

MT7987 features MediaTek NETSYS v3, similar to MT7988, features three GMACs
which support 2.5Gb HSGMII. One 2.5Gb PHY is also embedded an can be
connected to a dedicated GMAC.

Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>

mtk_eth.c contains not only the ethernet GMAC/DMA driver, but also
some ethernet switch initialization code. As we may add more switch
support in the future, it's better to move them out of mtk_eth.c to
avoid increasing the code complexity.

Since not all switches are supported for a particular board, Kconfig
options are added to allow user to select which switch should be
built into u-boot. If multiple switches are selected, auto-detecting
can also be enabled.

Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>