ARM: dts: renesas: Add missing ethernet PHY reset GPIO on Gen2 reference boards

ARM: dts: renesas: Add missing ethernet PHY reset GPIO on Gen2 reference boards

The ethernet PHY reset GPIO was missing and the kernel was depending
solely on the bootloader to bring the PHY out of reset. Fix this to
get rid of the dependency on bootloader.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Tested-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/20200115051225.7346-1-marek.vasut@gmail.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>