Revert "kbuild: Create directory for target DTB"

This reverts commit 77479b38.

Since commit 8a78756e ("kbuild: create object directories simpler
and faster"), all directories for 'targets' are created.

'mkdir -p $(dir ${dtc-tmp})' is no longer needed.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/Makefile.lib

@@ -303,8 +303,7 @@ $(obj)/%.dtb.S: $(obj)/%.dtb FORCE
 	$(call if_changed,dt_S_dtb)
 
 quiet_cmd_dtc = DTC     $@
-cmd_dtc = mkdir -p $(dir ${dtc-tmp}) ; \
-	$(HOSTCC) -E $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $< ; \
+cmd_dtc = $(HOSTCC) -E $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $< ; \
 	$(DTC) -O $(patsubst .%,%,$(suffix $@)) -o $@ -b 0 \
 		$(addprefix -i,$(dir $<) $(DTC_INCLUDE)) $(DTC_FLAGS) \
 		-d $(depfile).dtc.tmp $(dtc-tmp) ; \