arm64: dts: allwinner: teres-i: Remove wakekup-source from the PMIC

Neither the binding nor the driver make any use of the wakeup-source
property for the AXP803. Remove it.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20210901091852.479202-53-maxime@cerno.tech