dm ebs: fix a few typos

s/retrievd/retrieved/
s/misalignement/misalignment/
s/funtion/function/

Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>