arm64: dts: allwinner: h6: Use RSB for AXP805 PMIC connection

On boards where the only peripheral connected to PL0/PL1 is an X-Powers
PMIC, configure the connection to use the RSB bus rather than the I2C
bus. Compared to the I2C controller that shares the pins, the RSB
controller allows a higher bus frequency, and it is more CPU-efficient.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210103100007.32867-5-samuel@sholland.org