crypto: tcrypt - Do not bail on EINPROGRESS in multibuffer hash test

The multibuffer hash speed test is incorrectly bailing because
of an EINPROGRESS return value.  This patch fixes it by setting
ret to zero if it is equal to -EINPROGRESS.

Reported-by: Megha Dey <megha.dey@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>