post-fs-data.sh: Create directories with mkdir -p

`$mnt_dir` was not created with `mkdir -p`, unlike `$mnt_base`. This caused the system-ca-certs module to only work for the first boot after it was enabled, since `mkdir` would fail on subsequent boots.

Author: hexdefined

custota-tool/system-ca-certs/post-fs-data.sh

@@ -33,7 +33,7 @@ for cert_dir in "${apex_dir}" "${system_dir}"; do
     mnt_dir=${mnt_base}/${mnt_index}
     let mnt_index+=1
 
-    mkdir "${mnt_dir}"
+    mkdir -p "${mnt_dir}"
     nsenter --mount=/proc/1/ns/mnt -- \
         mount -t tmpfs "${module_id}" "${mnt_dir}"