These variables should not be shared with other image classes.
The bootimg class also has an HDDDIR variable that could be overwritten
if executing concurrently in the same image recipe.
(From OE-Core rev: 94c83fa26af104d28aa4e6951bcb109bb0c82265)
Signed-off-by: Jonathan Liu <net147@gmail.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>