uboot: Apply patches outside container

When running inside a rootless Podman container on a SELinux-enabled
host, the `patch` command fails because it cannot copy SELinux labels
from the original file to the patched file.  This only happens patching
files that are located in a bind mount.

patch-uboot.sh

@@ -0,0 +1,17 @@
+#!/bin/sh
+# vim: set sw=4 ts=4 sts=4 et :
+
+if [ -f u-boot/.patched ]; then
+    exit 0
+fi
+
+rc=0
+cd u-boot || exit
+for x in ../patches/uboot/*.patch; do
+    [ -f "${x}" ] || continue
+    printf 'Applying patch %s ...\n' "${x##*/}"
+    patch -p1 < "${x}" || rc=$?
+done
+if [ $rc -eq 0 ]; then
+    : > .patched
+fi