u-boot-clockworkpi-uconsole-radxa-cm5: rename from u-boot-radxa-cm5

* refactor to only target uconsole
* add update-u-boot tool

[ci:skip-vercheck]: not new package

Part-of: <https://gitlab.postmarketos.org/postmarketOS/pmaports/-/merge_requests/7918>

device/downstream/u-boot-clockworkpi-uconsole-radxa-cm5/use-python3.patch

@@ -0,0 +1,10 @@
+diff --git a/arch/arm/mach-rockchip/decode_bl31.py.orig b/arch/arm/mach-rockchip/decode_bl31.py
+index 42fa32d23..1cff8c3a4 100755
+--- a/arch/arm/mach-rockchip/decode_bl31.py.orig
++++ b/arch/arm/mach-rockchip/decode_bl31.py
+@@ -1,4 +1,4 @@
+-#!/usr/bin/env python2
++#!/usr/bin/env python3
+ #
+ # Copyright (C) 2020 Rockchip Electronics Co., Ltd
+ #