tools: ynl: use display hints for formatting of scalar attrs

Use display hints for formatting scalar attrs. This is specifically
useful for formatting IPv4 addresses carried typically as u32.

Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://patch.msgid.link/20240626201234.2572964-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/net/ynl/lib/ynl.py

@@ -743,6 +743,8 @@ def _decode(self, attrs, space, outer_attrs = None):
                 decoded = attr.as_scalar(attr_spec['type'], attr_spec.byte_order)
                 if 'enum' in attr_spec:
                     decoded = self._decode_enum(decoded, attr_spec)
+                elif attr_spec.display_hint:
+                    decoded = self._formatted_string(decoded, attr_spec.display_hint)
             elif attr_spec["type"] == 'indexed-array':
                 decoded = self._decode_array_attr(attr, attr_spec)
             elif attr_spec["type"] == 'bitfield32':