boards: ambiq: add adc to apollo4p boards

Add adc to apollo4 plus boards

Signed-off-by: Richard Wheatley <richard.wheatley@ambiq.com>

boards/ambiq/apollo4p_evb/apollo4p_evb-pinctrl.dtsi

@@ -17,6 +17,12 @@
 			input-enable;
 		};
 	};
+	adc0_default: adc0_default{
+		group1 {
+			pinmux = <ADCSE4_P15>, <ADCSE7_P12>;
+			drive-strength = "0.1";
+		};
+	};
 	i2c0_default: i2c0_default {
 		group1 {
 			pinmux = <M0SCL_P5>, <M0SDAWIR3_P6>;
@@ -81,7 +87,6 @@
 			bias-pull-up;
 		};
 	};
-
 	spi0_default: spi0_default {
 		group1 {
 			pinmux = <M0SCK_P5>, <M0MISO_P7>, <M0MOSI_P6>;

boards/ambiq/apollo4p_evb/apollo4p_evb.dts

@@ -63,6 +63,13 @@
 	status = "okay";
 };
 
+&adc0 {
+compatible = "ambiq,adc";
+	pinctrl-0 = <&adc0_default>;
+	pinctrl-names = "default";
+	status = "okay";
+};
+
 &counter0 {
 	status = "okay";
 };

boards/ambiq/apollo4p_evb/apollo4p_evb.yaml

@@ -15,6 +15,7 @@ supported:
   - spi
   - i2c
   - rtc
+  - adc
   - hwinfo
 testing:
   ignore_tags: