btrfs: remove unnecessary early exits in delalloc folio lock and unlock

btrfs: remove unnecessary early exits in delalloc folio lock and unlock

Inside functions unlock_delalloc_folio() and lock_delalloc_folios(), we
have the following early exits:

	if (index == locked_folio->index && end_index == index)
		return;

This allows us to exit early if the range is inside the same locked
folio.

However the current check relies on page sized folios, if we have a large
folio that contains @index but not at @index, then the early exit will
no longer trigger.

Furthermore without the above early check, the existing code can handle it
well, as both __process_folios_contig() and lock_delalloc_folios() will
skip any folio page lock/unlock if it's on the locked folio.

Here we remove the early exits and let the existing code handle the
same index case, to make the code a little simpler.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>