Merge branch 'tools-ynl-make-clean'

Jakub Kicinski says:

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tools: ynl: clean up make clean

First change renames the clean target which removes build results,
to a more common name. Second one add missing .PHONY targets.
Third one ensures that clean deletes __pycache__.

v2: add patch 2
v1: https://lore.kernel.org/all/20240301235609.147572-1-kuba@kernel.org/

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Signed-off-by: David S. Miller <davem@davemloft.net>