ARM: dtsi: axp81x: remove IP name from DT node name

The DT node should be named after its functionality and not after the
IP it's defining.

Signed-off-by: Quentin Schulz <quentin.schulz@bootlin.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>