Remove unnecessary else (and thus indentation level) from a code block
in ext4_xattr_block_set(). It will also make following code changes
easier. No functional changes.

CC: stable@vger.kernel.org
Fixes: 82939d79 ("ext4: convert to mbcache2")
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220712105436.32204-4-jack@suse.czSigned-off-by: Theodore Ts'o <tytso@mit.edu>