resize2fs: check number of group descriptors only if meta_bg is disabled

resize2fs: check number of group descriptors only if meta_bg is disabled

When meta_bg feature is enabled, the total number of group descriptors
is not really limiting the filesystem size. So there's no reason to
check it in that case. This allows resize2fs to resize filesystems past
256TB boundary similarly as the kernel can do it.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://lore.kernel.org/r/20240925171926.11354-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>