ext2: skip unnecessary operations in ext2_try_to_allocate()

Move 'repeat' tag to proper place so that we can
skip unnecessary operations in ext2_try_to_allocate().

Link: https://lore.kernel.org/r/20191104114036.9893-3-cgxu519@mykernel.net


Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
Signed-off-by: Jan Kara <jack@suse.cz>