dts/bindings/rtc/rtc-device.yaml: alarms-count optional

This commit makes the alarms-count dts property of the
rtc-device.yaml optional, setting the default to 0.

This simplifies the dts rtc dts node by not requiring
the property to be set to 0 if it is not supported.

Signed-off-by: Bjarki Arge Andreasen <[email protected]>

Author: Bjarki Arge Andreasen

dts/bindings/rtc/rtc-device.yaml

@@ -3,11 +3,13 @@
 
 include: base.yaml
 
-description: RTC device common bindings
+description: RTC (real-time clock) device common bindings
 
 properties:
   alarms-count:
     type: int
-    required: true
+    default: 0
     description: |
-      Number of alarms supported by RTC device
+      Number of alarms supported by RTC device. The number of
+      alarms defaults to 0, which indicates that the RTC has
+      no alarms.