dts/bindings: Move common properties into a base.yaml

Move common properties like 'compatible', 'reg', 'reg-names',
'interrupts', 'interrupt-names', and 'label' into one common base.yaml
that all the other yaml's can inherit from.  This removes both
duplication and inconsistent definition.

The device specific yamls just need to say if a property is 'required'
or not.

NOTE: due to some generation conflicts we did not covert
'soc-nv-flash.yaml' to use base.yaml.

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>

dts/bindings/riscv/openisa,rv32m1-pcc.yaml

@@ -10,25 +10,18 @@ version: 0.1
 description: >
     This is a representation of the RV32M1 PCC IP node
 
+inherits:
+    !include base.yaml
+
 properties:
     compatible:
-      type: string
-      category: required
-      description: compatible strings
       constraint: "openisa,rv32m1-pcc"
-      generation: define
 
     reg:
-      type: int
-      description: mmio register space
-      generation: define
       category: required
 
     label:
-      type: string
       category: required
-      description: Human readable string describing the device (used by Zephyr for API name)
-      generation: define
 
 "#cells":
   - name