crypto: stm32/hash - avoid error if maxburst not defined

dma-maxburst is an optional value and must not return
error in case of dma not used (or max-burst not defined).

Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
1 file changed