feat(dracut.sh): check if target kernel has zstd support compiled in

If compression option is zstd, check if target kernel supports it.
Otherwise, do not compress the initramfs image.

(cherry picked from commit 591118c)

Author: aafeijoo-suse

dracut.sh

@@ -2398,6 +2398,11 @@ case $compress in
         ;;
 esac
 
+if [[ $compress == $DRACUT_COMPRESS_ZSTD* ]] && ! check_kernel_config CONFIG_RD_ZSTD; then
+    dwarn "dracut: kernel has no zstd support compiled in."
+    compress="cat"
+fi
+
 if ! (
     umask 077
     cd "$initdir"