tools/net/ynl: Fix extack decoding for directional ops

NetlinkProtocol.decode() was looking up ops by response value which breaks
when it is used for extack decoding of directional ops. Instead, pass
the op to decode().

Signed-off-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://lore.kernel.org/r/20240418104737.77914-3-donald.hunter@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>