wic: generate PARTUUID for MDOS partitions
Added generation of partition UUIDs for MSDOS partitions.
UUID for MSDOS partitions is <disk identifier>-<partition number>,
where disk identifier is a random 4 bytes long number. It's usually
generated when MBR/partition table is initialized.
As UUID is used to point to the root partition in bootloader config
we need to generate it before the MBR is initialized.
After MBR is created we need to rewrite system identifier to match
it with what is used in bootloader config. This will be implemented
in the next commit.
Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
