ARM: dts: sun8i: Adjust power key nodes

Several H3 and one H2+ board have power key nodes, which are slightly
off. Some are missing wakeup-source property and some have BTN_0 code
assigned instead of KEY_POWER.

Adjust them, so they can function as intended by designer.

Co-developed-by: Michael Klein <michael@fossekall.de>
Signed-off-by: Michael Klein <michael@fossekall.de>
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20211129165510.370717-1-jernej.skrabec@gmail.com