Some mmc cards do not have all the data files in /sys/block
populated. Check for existence before displaying the files
to avoid erroring out of the install process.
(From OE-Core rev: 1d73e3f9d9977382efdb0c111c556c6048bd60b4)
Signed-off-by: Drew Moseley <drew_moseley@mentor.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>