tools/net/ynl: Encode default values for binary blobs

Add support for defaulting binary byte arrays to all zeros as well as
defaulting scalar values to 0 when encoding input parameters.
Signed-off-by: Donald Hunter <donald.hunter@gmail.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20240129223458.52046-7-donald.hunter@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

tools/net/ynl/lib/ynl.py

@@ -742,12 +742,17 @@ class YnlFamily(SpecFamily):
         members = self.consts[name].members
         attr_payload = b''
         for m in members:
-            value = vals.pop(m.name) if m.name in vals else 0
+            value = vals.pop(m.name) if m.name in vals else None
             if m.type == 'pad':
                 attr_payload += bytearray(m.len)
             elif m.type == 'binary':
-                attr_payload += bytes.fromhex(value)
+                if value is None:
+                    attr_payload += bytearray(m.len)
+                else:
+                    attr_payload += bytes.fromhex(value)
             else:
+                if value is None:
+                    value = 0
                 format = NlAttr.get_format(m.type, m.byte_order)
                 attr_payload += format.pack(value)
         return attr_payload