dts: bindings: clean up redundant required false attributes

DTS property attributes are (by default) not required.

Explicitly specifying `required: false` is redundant.
Perhaps a warning to that effect would be useful.

Signed-off-by: Chris Friedt <cfriedt@meta.com>

dts/bindings/rtc/maxim,ds3231.yaml

@@ -16,7 +16,6 @@ properties:
 
   32k-gpios:
     type: phandle-array
-    required: false
     description: |
 
       32 KiHz open drain output
@@ -27,7 +26,6 @@ properties:
 
   isw-gpios:
     type: phandle-array
-    required: false
     description: |
 
       interrupt/square wave open drain output

dts/bindings/rtc/microchip,mcp7940n.yaml

@@ -16,7 +16,6 @@ properties:
 
   int-gpios:
     type: phandle-array
-    required: false
     description: |
 
       Host input connected to the MCP7940N MFP open drain output pin

dts/bindings/rtc/nordic,nrf-rtc.yaml

@@ -26,7 +26,6 @@ properties:
     ppi-wrap:
       type: boolean
       description: Enable wrapping with PPI
-      required: false
 
    # If enabled then counter based on nRF RTC peripheral supports only maximal
    # top value. That results in code optimizations and availability of one more
@@ -34,4 +33,3 @@ properties:
     fixed-top:
       type: boolean
       description: Enable fixed top value
-      required: false

dts/bindings/rtc/nxp,kinetis-lptmr.yaml

@@ -24,10 +24,8 @@ properties:
 
     input-pin:
       type: int
-      required: false
       description: Pulse counter input pin (0 to 3).
 
     active-low:
       type: boolean
-      required: false
       description: Pulse counter input pin is active-low

dts/bindings/rtc/rtc.yaml

@@ -8,12 +8,10 @@ include: base.yaml
 properties:
     clock-frequency:
       type: int
-      required: false
       description: Clock frequency information for RTC operation
     interrupts:
       required: true
 
     prescaler:
       type: int
-      required: false
       description: RTC frequency equals clock-frequency divided by the prescaler value

dts/bindings/rtc/xlnx,xps-timer-1.00.a.yaml

@@ -23,7 +23,6 @@ properties:
 
     xlnx,gen0-assert:
       type: int
-      required: false
       enum:
         - 0
         - 1
@@ -33,7 +32,6 @@ properties:
 
     xlnx,gen1-assert:
       type: int
-      required: false
       enum:
         - 0
         - 1
@@ -52,7 +50,6 @@ properties:
 
     xlnx,trig0-assert:
       type: int
-      required: false
       enum:
         - 0
         - 1
@@ -62,7 +59,6 @@ properties:
 
     xlnx,trig1-assert:
       type: int
-      required: false
       enum:
         - 0
         - 1