scripts/mkimg.arm.sh: fix inclusion of u-boot-pine64

fix the sed extression that filters out version number sot it does not
strip out the `-pine64` part of string.

  apk fetch  --simulate --root --recursive u-boot-all

scripts/mkimg.arm.sh

@@ -96,7 +96,7 @@ profile_rpi() {
 build_uboot() {
 	set -x
 	# FIXME: Fix apk-tools to extract packages directly
-	local pkg pkgs="$(apk fetch  --simulate --root "$APKROOT" --recursive u-boot-all | sed -ne "s/^Downloading \([^0-9.]*\)\-.*$/\1/p")"
+	local pkg pkgs="$(apk fetch  --simulate --root "$APKROOT" --recursive u-boot-all | sed -ne "s/^Downloading \(.*\)\-[0-9].*$/\1/p")"
 	for pkg in $pkgs; do
 		[ "$pkg" = "u-boot-all" ] || apk fetch --root "$APKROOT" --stdout $pkg | tar -C "$DESTDIR" -xz usr
 	done