dt-bindings: Fix dt_binding_check target for in tree builds

On in tree builds, subsequent builds will incorrectly include
the intermediate file 'processed-schema.yaml' with the input schema
files resulting in a build error. Update the find command to ignore
processed-schema.yaml.
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/Makefile

@@ -17,7 +17,11 @@ extra-y += $(DT_TMP_SCHEMA)
 quiet_cmd_mk_schema = SCHEMA  $@
       cmd_mk_schema = $(DT_MK_SCHEMA) $(DT_MK_SCHEMA_FLAGS) -o $@ $(filter-out FORCE, $^)
 
-DT_DOCS = $(shell cd $(srctree)/$(src) && find * -name '*.yaml')
+DT_DOCS = $(shell \
+	cd $(srctree)/$(src) && \
+	find * \( -name '*.yaml' ! -name $(DT_TMP_SCHEMA) \) \
+	)
+
 DT_SCHEMA_FILES ?= $(addprefix $(src)/,$(DT_DOCS))
 
 extra-y += $(patsubst $(src)/%.yaml,%.example.dts, $(DT_SCHEMA_FILES))