crypto: img-hash - Add Imagination Technologies hw hash accelerator

This adds support for the Imagination Technologies hash accelerator which
provides hardware acceleration for SHA1 SHA224 SHA256 and MD5 hashes.

Signed-off-by: James Hartley <james.hartley@imgtec.com>
Reviewed-by: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>