ext4: replace kmem_cache_create with KMEM_CACHE

Replace kmem_cache_create with KMEM_CACHE macro that
guaranteed struct alignment

Signed-off-by: JunChao Sun <sunjunchao2870@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20221109153822.80250-1-sunjunchao2870@gmail.com


Signed-off-by: Theodore Ts'o <tytso@mit.edu>