ARM: dts: qcom: pmx55: align SPMI PMIC Power-on node name with dtschema

Bindings expect Power-on node name to be "pon":

'power-on@800' do not match any of the regexes

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Reviewed-by: David Heidelberg <[e-mail]>
Reviewed-by: Stephen Boyd <[e-mail]>
Reviewed-by: Vinod Koul <[e-mail]>
Signed-off-by: Bjorn Andersson <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/arm/boot/dts/qcom-pmx55.dtsi

···
 		#address-cells = <1>;
 		#size-cells = <0>;
 
-		power-on@800 {
+		pon@800 {
 			compatible = "qcom,pm8916-pon";
 			reg = <0x0800>;