The original move of the mkefidisk code to the bootimg-efi plugin
resulted in a bad hdddir - fix it.
(From OE-Core rev: ab337705521d8734f12be612709e70a163111fe3)
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>