arm64: dts: allwinner: a64: sopine-baseboard: Add PHY regulator delay

It turns out that sopine-baseboard needs same fix as pine64-plus
for ethernet PHY. Here too Realtek ethernet PHY chip needs additional
power on delay to properly initialize. Datasheet mentions that chip
needs 30 ms to be properly powered on and that it needs some more time
to be initialized.

Fix that by adding 100ms ramp delay to regulator responsible for
powering PHY.

Note that issue was found out and fix tested on pine64-lts, but it's
basically the same as sopine-baseboard, only layout and connectors
differ.

Fixes: bdfe4ceb ("arm64: allwinner: a64: add Ethernet PHY regulator for several boards")
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <mripard@kernel.org>