uboot-sifiveu: use intree dtc explicitly

This replaces pylibfdt hack.

Signed-off-by: Tianling Shen <cnsztl@immortalwrt.org>

package/boot/uboot-sifiveu/Makefile

@@ -10,6 +10,8 @@ PKG_RELEASE:=1
 PKG_VERSION:=2022.10
 PKG_HASH:=50b4482a505bc281ba8470c399a3c26e145e29b23500bc35c50debd7fa46bdf8
 
+UBOOT_USE_INTREE_DTC:=1
+
 include $(INCLUDE_DIR)/u-boot.mk
 include $(INCLUDE_DIR)/package.mk
 

package/boot/uboot-sifiveu/patches/300-force-pylibfdt-build.patch

@@ -1,30 +0,0 @@
---- a/Makefile
-+++ b/Makefile
-@@ -2028,26 +2028,7 @@ endif
- # Check dtc and pylibfdt, if DTC is provided, else build them
- PHONY += scripts_dtc
- scripts_dtc: scripts_basic
--	$(Q)if test "$(DTC)" = "$(DTC_INTREE)"; then \
--		$(MAKE) $(build)=scripts/dtc; \
--	else \
--		if ! $(DTC) -v >/dev/null; then \
--			echo '*** Failed to check dtc version: $(DTC)'; \
--			false; \
--		else \
--			if test "$(call dtc-version)" -lt $(DTC_MIN_VERSION); then \
--				echo '*** Your dtc is too old, please upgrade to dtc $(DTC_MIN_VERSION) or newer'; \
--				false; \
--			else \
--				if [ -n "$(CONFIG_PYLIBFDT)" ]; then \
--					if ! echo "import libfdt" | $(PYTHON3) 2>/dev/null; then \
--						echo '*** pylibfdt does not seem to be available with $(PYTHON3)'; \
--						false; \
--					fi; \
--				fi; \
--			fi; \
--		fi; \
--	fi
-+	$(MAKE) $(build)=scripts/dtc
- 
- # ---------------------------------------------------------------------------
- quiet_cmd_cpp_lds = LDS     $@