crypto: omap-aes - avoid spamming console with self tests

Running the self test suite for omap-aes with extra tests enabled causes
huge spam with the tag message wrong indicators. With self tests, this
is fine as there are some tests that purposedly pass bad data to the
driver. Also, returning -EBADMSG from the driver is enough, so remove the
dev_err message completely.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>