scripts/contrib/ddimage: replace blacklist with mount check

scripts/contrib/ddimage: replace blacklist with mount check

The blacklist, whilst previously useful for safety, is now becoming
obsolete - on my current system, the main storage is at /dev/nvme* and
if I plug in a USB stick it shows up as /dev/sdb which was previously
blacklisted. To make this more flexible, remove the blacklist and
instead check if the specified device is mounted, has a partition
that is mounted, or is otherwise in use according to the kernel, and
show an appropriate error and quit if so.

To make this robust, also ensure we handle where the specified device is
a symlink to another device.

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>