tools: ynl-gen: use enum names in op strmap more carefully

tools: ynl-gen: use enum names in op strmap more carefully

In preparation for supporting families which use different msg
ids to and from the kernel - make sure the ids in op strmap
are correct. The map is expected to be used mostly for notifications,
don't generate a separate map for the "to kernel" direction.

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