Devicetree: edtlib: fix possible AttributeError in Property.description

Attempting to access the property Property.description
when Property.spec.description is None would raise
AttributeError: 'NoneType' object has no attribute 'strip'.

Known properties that may not have a description
(Property.spec.description is None):
- 'compatible' for nodes such as / /soc /soc/timer@e000e010 /leds /pwmleds
- 'reg'        for nodes such as /soc/timer@e000e010
- 'status'     for nodes such as /soc/timer@e000e010
- 'gpios'      for nodes such as /leds/led_0 /buttons/button_0
- 'pwms'       for nodes such as /pwmleds/pwm_led_0

This patch checks the PropertySpec.description attribute before calling
strip(): will return None, and not raise AttributeError.

Signed-off-by: Chris Duf <chris@openmarl.org>

Co-authored-by: Gerard Marull-Paretas <gerard@teslabs.com>

scripts/dts/python-devicetree/src/devicetree/edtlib.py

@@ -1610,8 +1610,8 @@ class Property:
       Convenience for spec.name.
 
     description:
-      Convenience for spec.name with leading and trailing whitespace
-      (including newlines) removed.
+      Convenience for spec.description with leading and trailing whitespace
+      (including newlines) removed. May be None.
 
     type:
       Convenience for spec.type.
@@ -1655,7 +1655,7 @@ def name(self):
     @property
     def description(self):
         "See the class docstring"
-        return self.spec.description.strip()
+        return self.spec.description.strip() if self.spec.description else None
 
     @property
     def type(self):