dts: bindings: drop "required: false" from base binding

It's redundant and it's failing the compliance CI check.

Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>

dts/bindings/base/base.yaml

@@ -5,7 +5,6 @@ include: [pm.yaml]
 properties:
     status:
         type: string
-        required: false
         description: indicates the operational status of a device
         enum:
            - "ok" # Deprecated form
@@ -23,16 +22,13 @@ properties:
     reg:
         type: array
         description: register space
-        required: false
 
     reg-names:
         type: string-array
         description: name of each register space
-        required: false
 
     interrupts:
         type: array
-        required: false
         description: interrupts for device
 
     # Does not follow the 'type: phandle-array' scheme, but gets type-checked
@@ -40,73 +36,59 @@ properties:
     # 'required: true' easily if they want to.
     interrupts-extended:
         type: compound
-        required: false
         description: extended interrupt specifier for device
 
     interrupt-names:
         type: string-array
-        required: false
         description: name of each interrupt
 
     interrupt-parent:
         type: phandle
-        required: false
         description: phandle to interrupt controller node
 
     label:
         type: string
-        required: false
         deprecated: true
         description: |
           Human readable string describing the device (used as device_get_binding() argument)
 
     clocks:
         type: phandle-array
-        required: false
         description: Clock gate information
 
     clock-names:
         type: string-array
-        required: false
         description: name of each clock
 
     "#address-cells":
         type: int
-        required: false
         description: number of address cells in reg property
 
     "#size-cells":
         type: int
-        required: false
         description: number of size cells in reg property
 
     dmas:
-      required: false
       type: phandle-array
       description: DMA channels specifiers
 
     dma-names:
-      required: false
       type: string-array
       description: Provided names of DMA channel specifiers
 
     io-channels:
-      required: false
       type: phandle-array
       description: IO channels specifiers
 
     io-channel-names:
-      required: false
       type: string-array
       description: Provided names of IO channel specifiers
 
     mboxes:
-      required: false
       type: phandle-array
       description: mailbox / IPM channels specifiers
       specifier-space: mbox
 
     mbox-names:
-      required: false
       type: string-array
       description: Provided names of mailbox / IPM channel specifiers