uboot-rockchip: update to v2020.07

Update the U-Boot to version v2020.07. Also replace the Makefile rewrite
with a proper patch, explaining why this hack is needed.

Run-tested: FriendlyARM NanoPi R2S

Signed-off-by: David Bauer <mail@david-bauer.net>

package/boot/uboot-rockchip/Makefile

@@ -5,9 +5,9 @@
 include $(TOPDIR)/rules.mk
 include $(INCLUDE_DIR)/kernel.mk
 
-PKG_VERSION:=2020.04
+PKG_VERSION:=2020.07
 
-PKG_HASH:=fe732aaf037d9cc3c0909bad8362af366ae964bbdac6913a34081ff4ad565372
+PKG_HASH:=c1f5bf9ee6bb6e648edbf19ce2ca9452f614b08a9f886f1a566aa42e8cf05f6a
 
 PKG_MAINTAINER:=Tobias Maedel <openwrt@tbspace.de>
 
@@ -38,7 +38,6 @@ UBOOT_MAKE_FLAGS += \
   BL31=$(STAGING_DIR_IMAGE)/rk3399_bl31.elf
 
 define Build/Configure
-	$(SED) s/subdir.*pylibfdt//g $(PKG_BUILD_DIR)/scripts/dtc/Makefile
 	$(call Build/Configure/U-Boot)
 
 	$(SED) 's#CONFIG_MKIMAGE_DTC_PATH=.*#CONFIG_MKIMAGE_DTC_PATH="$(PKG_BUILD_DIR)/scripts/dtc/dtc"#g' $(PKG_BUILD_DIR)/.config

package/boot/uboot-rockchip/patches/001-scripts-remove-dependency-on-swig.patch

@@ -0,0 +1,24 @@
+From b137ca16b54c67d76714ea5a0138741959b0dc29 Mon Sep 17 00:00:00 2001
+From: David Bauer <mail@david-bauer.net>
+Date: Mon, 13 Jul 2020 23:37:37 +0200
+Subject: [PATCH] scripts: remove dependency on swig
+
+Don't build the libfdt tool, as it has a dependency on swig (which
+OpenWrt does not ship).
+
+This requires more hacks, as of-platdata generation does not work
+without it.
+
+Signed-off-by: David Bauer <mail@david-bauer.net>
+---
+ scripts/dtc/Makefile | 2 --
+ 1 file changed, 2 deletions(-)
+
+--- a/scripts/dtc/Makefile
++++ b/scripts/dtc/Makefile
+@@ -18,5 +18,3 @@ HOSTCFLAGS_dtc-parser.tab.o := -I$(src)
+ # dependencies on generated files need to be listed explicitly
+ $(obj)/dtc-lexer.lex.o: $(obj)/dtc-parser.tab.h
+ 
+-# Added for U-Boot
+-subdir-$(CONFIG_PYLIBFDT) += pylibfdt