fs/ext2: Ignore the large_dir incompat feature

fs/ext2: Ignore the large_dir incompat feature

Recently, ext4 added the large_dir feature, which adds support for
a 3 level htree directory support.

The GRUB supports existing file systems with htree directories by
ignoring their existence, and since the index nodes for the hash tree
look like deleted directory entries (by design), the GRUB can simply do
a brute force O(n) linear search of directories. The same is true for
3 level deep htrees indicated by large_dir feature flag.

Hence, it is safe for the GRUB to ignore the large_dir incompat feature.

Fixes: https://savannah.gnu.org/bugs/?61606
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>