tools: ynl-gen: fix parse multi-attr enum attribute

When attribute is enum type and marked as multi-attr, the netlink
respond is not parsed, fails with stack trace:
Traceback (most recent call last):
File "/net-next/tools/net/ynl/./test.py", line 520, in <module>
main()
File "/net-next/tools/net/ynl/./test.py", line 488, in main
dplls=dplls_get(282574471561216)
File "/net-next/tools/net/ynl/./test.py", line 48, in dplls_get
reply=act(args)
File "/net-next/tools/net/ynl/./test.py", line 41, in act
reply = ynl.dump(args.dump, attrs)
File "/net-next/tools/net/ynl/lib/ynl.py", line 598, in dump
return self._op(method, vals, dump=True)
File "/net-next/tools/net/ynl/lib/ynl.py", line 584, in _op
rsp_msg = self._decode(gm.raw_attrs, op.attr_set.name)
File "/net-next/tools/net/ynl/lib/ynl.py", line 451, in _decode
self._decode_enum(rsp, attr_spec)
File "/net-next/tools/net/ynl/lib/ynl.py", line 408, in _decode_enum
value = enum.entries_by_val[raw].name
TypeError: unhashable type: 'list'
error: 1

Redesign _decode_enum(..) to take a enum int value and translate
it to either a bitmask or enum name as expected.

Signed-off-by: Arkadiusz Kubalewski <[e-mail]>
Reviewed-by: Donald Hunter <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Jakub Kicinski <[e-mail]>
Signed-off-by: Jakub Kicinski <[e-mail]>

tools/net/ynl/lib/ynl.py

···
         pad = b'\x00' * ((4 - len(attr_payload) % 4) % 4)
         return struct.pack('HH', len(attr_payload) + 4, nl_type) + attr_payload + pad
 
-    def _decode_enum(self, rsp, attr_spec):
-        raw = rsp[attr_spec['name']]
+    def _decode_enum(self, raw, attr_spec):
         enum = self.consts[attr_spec['enum']]
         if 'enum-as-flags' in attr_spec and attr_spec['enum-as-flags']:
             i = 0
···
                 i += 1
         else:
             value = enum.entries_by_val[raw].name
-        rsp[attr_spec['name']] = value
+        return value
 
     def _decode_binary(self, attr, attr_spec):
         if attr_spec.struct_name:
···
             decoded = attr.as_struct(members)
             for m in members:
                 if m.enum:
-                    self._decode_enum(decoded, m)
+                    decoded[m.name] = self._decode_enum(decoded[m.name], m)
         elif attr_spec.sub_type:
             decoded = attr.as_c_array(attr_spec.sub_type)
         else:
···
             else:
                 raise Exception(f'Unknown {attr_spec["type"]} with name {attr_spec["name"]}')
 
+            if 'enum' in attr_spec:
+                decoded = self._decode_enum(decoded, attr_spec)
+
             if not attr_spec.is_multi:
                 rsp[attr_spec['name']] = decoded
             elif attr_spec.name in rsp:
···
             else:
                 rsp[attr_spec.name] = [decoded]
 
-            if 'enum' in attr_spec:
-                self._decode_enum(rsp, attr_spec)
         return rsp
 
     def _decode_extack_path(self, attrs, attr_set, offset, target):