Remove obsolete_counts from grub2 compatibility list

PR#15459 add all read-only compatible zpool features to grub2
compatibility list. 'obsolete_counts' is a read-only features that
depends on 'device_removal' feature which is not read-only and
is marked as ZFEATURE_FLAG_MOS. Creating a pool with grub2
compatibility enables 'device_removal' feature as well, which is
not desired.

This commit removes the 'obsolete_counts' feature from
grub2 compatibility list, as GRUB only supports read-only
compatible features.

Reviewed-by: George Melikov <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Alexander Motin <[email protected]>
Signed-off-by: Umer Saleem <[email protected]>
Closes #15499

Author: Umer Saleem

cmd/zpool/compatibility.d/grub2

@@ -14,7 +14,6 @@ large_blocks
 livelist
 log_spacemap
 lz4_compress
-obsolete_counts
 project_quota
 resilver_defer
 spacemap_histogram