dt-bindings: kbuild: Split targets out to separate rules

Masahiro pointed out the use of if_changed_rule is incorrect and command
line changes are not correctly accounted for.

To fix this, split up the DT binding validation target,
dt_binding_check, into multiple rules for each step: yamllint, schema
validtion with meta-schema, and building the processed schema.

One change in behavior is the yamllint or schema validation will be
re-run again when there are warnings present.

Reported-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/all/20220817152027.16928-1-masahiroy@kernel.org/


Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>