zed: Ignore false 'atari' partitions in autoreplace

libudev will sometimes falsely identify an 'atari' partition on a
blank disk, preventing it from being used in an autoreplace. This
seems to be a known issue. The workaround is to just ignore the
fake partition and continue with the autoreplace.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #13497
Closes #13632