On the first vdev open ignore impossible ashift hints

If on the first open device's logical ashift is bigger than set
by pool's ashift property, ignore the last as unusable instead of
creating vdev that will fail most of I/Os due to misalignment.

Reviewed-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ameer Hamza <ahamza@ixsystems.com>
Signed-off-by:  Alexander Motin <mav@FreeBSD.org>
Sponsored by:   iXsystems, Inc.
Closes #16690

module/zfs/vdev.c

@@ -2205,10 +2205,11 @@ vdev_open(vdev_t *vd)
 		vd->vdev_max_asize = max_asize;
 
 		/*
-		 * If the vdev_ashift was not overridden at creation time,
+		 * If the vdev_ashift was not overridden at creation time
+		 * (0) or the override value is impossible for the device,
 		 * then set it the logical ashift and optimize the ashift.
 		 */
-		if (vd->vdev_ashift == 0) {
+		if (vd->vdev_ashift < vd->vdev_logical_ashift) {
 			vd->vdev_ashift = vd->vdev_logical_ashift;
 
 			if (vd->vdev_logical_ashift > ASHIFT_MAX) {