packages: nftables: fix build on host with busybox ash

Numeric for loops are a bashism and won't work in BusyBox' ash. Replace
with a portable equivalent.

Backport of a post-1.1.6 nftables fix.

Signed-off-by: Shine <4c.fce2@proton.me>
Link: https://github.com/openwrt/openwrt/pull/21957
Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>

package/network/utils/nftables/patches/001-for-bash-syntax.patch

@@ -0,0 +1,11 @@
+--- a/configure
++++ b/configure
+@@ -17940,7 +17940,7 @@
+ 	echo "	${STABLE_RELEASE}"
+ 	echo "};"
+ 	echo "static char nftbuildstamp[] = {"
+-	for ((i = 56; i >= 0; i-= 8)); do
++	for i in `seq 56 -8 0`; do
+ 		echo "	((uint64_t)MAKE_STAMP >> $i) & 0xff,"
+ 	done
+ 	echo "};"