crypto: stm32 - fix MDMAT condition

If IP has MDMAT support, set or reset the bit MDMAT in Control Register.

Fixes: b56403a2 ("crypto: stm32/hash - Support Ux500 hash")
Cc: stable@vger.kernel.org
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Thomas Bourgoin <thomas.bourgoin@foss.st.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>