tools: ynl: use 'cond is None'

It is better to use the 'is' keyword instead of comparing to None
according to Ruff.

This is linked to Ruff error E711 [1]:

  According to PEP 8, "Comparisons to singletons like None should always
  be done with is or is not, never the equality operators."

Link: https://docs.astral.sh/ruff/rules/none-comparison/ [1]
Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
Reviewed-by: Donald Hunter <[email protected]>
Reviewed-by: Asbjørn Sloth Tønnesen <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: matttbe

tools/net/ynl/pyynl/lib/ynl.py

@@ -705,7 +705,7 @@ def _decode_unknown(self, attr):
             return attr.as_bin()
 
     def _rsp_add(self, rsp, name, is_multi, decoded):
-        if is_multi == None:
+        if is_multi is None:
             if name in rsp and type(rsp[name]) is not list:
                 rsp[name] = [rsp[name]]
                 is_multi = True

tools/net/ynl/pyynl/ynl_gen_c.py

@@ -397,7 +397,7 @@ def _init_checks(self):
         if 'enum' in self.attr:
             enum = self.family.consts[self.attr['enum']]
             low, high = enum.value_range()
-            if low == None and high == None:
+            if low is None and high is None:
                 self.checks['sparse'] = True
             else:
                 if 'min' not in self.checks: