dts: arm: st: correct npgios for all stm32 gpio controllers

For almost all STM32 GPIO controllers, the number of supported GPIO
pins managed by a single controller is 16 (with some exceptions for
fewer). However, the default for ngpios in the device tree bindings
for gpio-controllers is 32; leading to inaccuracies in handling GPIO
for these controllers, such as presenting too many GPIOs in the GPIO
shell. This patch redefines the default for ngpios for "st,stm32-gpio"
compatible devices to 16 and adds the correct ngpios for the few
exceptions Zephyr current supports.

Signed-off-by: Michael R Rosen <mrrosen@alumni.cmu.edu>

dts/arm/st/l4/stm32l496.dtsi

@@ -44,6 +44,7 @@
 				compatible = "st,stm32-gpio";
 				gpio-controller;
 				#gpio-cells = <2>;
+				ngpios = <12>;
 				reg = <0x48002000 0x400>;
 				clocks = <&rcc STM32_CLOCK_BUS_AHB2 0x00000100>;
 			};

dts/arm/st/wb/stm32wb.dtsi

@@ -228,6 +228,7 @@
 				compatible = "st,stm32-gpio";
 				gpio-controller;
 				#gpio-cells = <2>;
+				ngpios = <5>;
 				reg = <0x48001000 0x400>;
 				clocks = <&rcc STM32_CLOCK_BUS_AHB2 0x00000010>;
 			};
@@ -236,6 +237,7 @@
 				compatible = "st,stm32-gpio";
 				gpio-controller;
 				#gpio-cells = <2>;
+				ngpios = <4>;
 				reg = <0x48001c00 0x400>;
 				clocks = <&rcc STM32_CLOCK_BUS_AHB2 0x00000080>;
 			};

dts/bindings/gpio/st,stm32-gpio.yaml

@@ -5,7 +5,11 @@ description: STM32 GPIO node
 
 compatible: "st,stm32-gpio"
 
-include: [gpio-controller.yaml, base.yaml]
+include:
+  - name: gpio-controller.yaml
+    property-blocklist:
+      - ngpios
+  - name: base.yaml
 
 properties:
   reg:
@@ -17,6 +21,19 @@ properties:
   "#gpio-cells":
     const: 2
 
+  ngpios:
+    type: int
+    default: 16
+    description: |
+        This property indicates the number of in-use slots of available slots
+        for GPIOs. The STM32 GPIO controller typically has all 16 possible port
+        IO with few exceptions. It should only be necessary to explicitly set
+        this property if the controller itself does not implement all 16 port
+        IO register bits; for example PORTE in the STM32WB55xx series which only
+        implements the first 5. Package restrictions on the number of exposed
+        GPIO should not influence this property. For cases in which there might
+        be holes in the slot range, this value should be the max slot number+1.
+
 gpio-cells:
   - pin
   - flags