dt-bindings: input: touchscreen: imagis: add missing minItems

The binding currently expects exactly 5 keycodes, which matches the
chip's theoretical maximum but probably not the number of touch keys on
any phone using the IST3032C. Add a minItems value of 2 to prevent
dt-validate complaints.

Also add another example to make sure the linux,keycodes property is
checked.

Signed-off-by: Duje Mihanović <[e-mail]>
Acked-by: Conor Dooley <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dmitry Torokhov <[e-mail]>

Documentation/devicetree/bindings/input/touchscreen/imagis,ist3038c.yaml

···
 
   linux,keycodes:
     description: Keycodes for the touch keys
+    minItems: 2
     maxItems: 5
 
   touchscreen-size-x: true
···
         touchscreen-fuzz-y = <10>;
         touchscreen-inverted-x;
         touchscreen-inverted-y;
+      };
+    };
+  - |
+    #include <dt-bindings/input/linux-event-codes.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      touchscreen@50 {
+        compatible = "imagis,ist3032c";
+        reg = <0x50>;
+        interrupt-parent = <&gpio>;
+        interrupts = <72 IRQ_TYPE_EDGE_FALLING>;
+        vdd-supply = <&ldo2>;
+        touchscreen-size-x = <480>;
+        touchscreen-size-y = <800>;
+        linux,keycodes = <KEY_APPSELECT>, <KEY_BACK>;
       };
     };