crypto: ux500/hash: add missing static qualifiers

Add missing static qualifiers to hash_process_data and hash_hw_final.

Signed-off-by: Fabio Baltieri <fabio.baltieri@linaro.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>