Don't check for SPA_MINDEVSIZE in vdev_geom_attach when opening by path.
It's redundant with the check in vdev_open, and failing to attach here
results in the wrong error message being printed. However, still check for
it in some other situations:
* When opening by guids, so we don't get bogged down reading from slow
devices like floppy drives.
* In vdev_geom_read_pool_label for the same reason, because we iterate over
all providers.
* If the caller requests that we verify the guid, because then we'll have to
read from the device before vdev_open verifies the size.
PR: 222227
Reported by: Marie Helene Kvello-Aune <marieheleneka@gmail.com>
Reviewed by: avg, mav
MFC after: 3 weeks
Sponsored by: Spectra Logic Corp
Differential Revision: https://reviews.freebsd.org/D12531
659058b06f