dt-bindings: hisilicon,hi6421-spmi-pmic.yaml: make some rules stricter

Define maxItems for interrupts and accept only "ldo" in lower case.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/b7a775808d9c3a87fbe1c5a6dd71f8f18be7e649.1627116034.git.mchehab+huawei@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/mfd/hisilicon,hi6421-spmi-pmic.yaml

@@ -34,7 +34,8 @@ properties:
 
   interrupt-controller: true
 
-  interrupts: true
+  interrupts:
+    maxItems: 1
 
   regulators:
     type: object
@@ -49,7 +50,7 @@ properties:
         const: 0
 
     patternProperties:
-      '^(ldo|LDO)[0-9]+$':
+      '^ldo[0-9]+$':
         type: object
 
         $ref: "/schemas/regulator/regulator.yaml#"
@@ -79,55 +80,55 @@ examples:
         #address-cells = <1>;
         #size-cells = <0>;
 
-        ldo3: LDO3 {
+        ldo3: ldo3 {
           regulator-name = "ldo3";
           regulator-min-microvolt = <1500000>;
           regulator-max-microvolt = <2000000>;
           regulator-boot-on;
         };
 
-        ldo4: LDO4 {
+        ldo4: ldo4 {
           regulator-name = "ldo4";
           regulator-min-microvolt = <1725000>;
           regulator-max-microvolt = <1900000>;
           regulator-boot-on;
         };
 
-        ldo9: LDO9 {
+        ldo9: ldo9 {
           regulator-name = "ldo9";
           regulator-min-microvolt = <1750000>;
           regulator-max-microvolt = <3300000>;
           regulator-boot-on;
         };
 
-        ldo15: LDO15 {
+        ldo15: ldo15 {
           regulator-name = "ldo15";
           regulator-min-microvolt = <1800000>;
           regulator-max-microvolt = <3000000>;
           regulator-always-on;
         };
 
-        ldo16: LDO16 {
+        ldo16: ldo16 {
           regulator-name = "ldo16";
           regulator-min-microvolt = <1800000>;
           regulator-max-microvolt = <3000000>;
           regulator-boot-on;
         };
 
-        ldo17: LDO17 {
+        ldo17: ldo17 {
           regulator-name = "ldo17";
           regulator-min-microvolt = <2500000>;
           regulator-max-microvolt = <3300000>;
         };
 
-        ldo33: LDO33 {
+        ldo33: ldo33 {
           regulator-name = "ldo33";
           regulator-min-microvolt = <2500000>;
           regulator-max-microvolt = <3300000>;
           regulator-boot-on;
         };
 
-        ldo34: LDO34 {
+        ldo34: ldo34 {
           regulator-name = "ldo34";
           regulator-min-microvolt = <2600000>;
           regulator-max-microvolt = <3300000>;