in hash init code preserve constness

This causes warnings in some our builds as can be seen in some
smoke reports:

  zaphod32_hash.h:185:17: warning: cast discards '__attribute__((const))'
  qualifier from pointer target type [-Wcast-qual]

1 files changed, 1 insertions, 1 deletions

diff --git a/sbox32_hash.h b/sbox32_hash.h
index 9c98195899..748256c71c 100644
--- a/sbox32_hash.h
+++ b/sbox32_hash.h
@@ -1421,7 +1421,7 @@ SBOX32_STATIC_INLINE void sbox32_seed_state96 (
     const U8 *seed_ch,
     U8 *state_ch
 ) {
-    U32 *seed= (U32 *)seed_ch;
+    const U32 *seed= (const U32 *)seed_ch;
     U32 *state= (U32 *)state_ch;
     U32 *state_cursor = state + 1;
     U32 *sbox32_end = state + 1 + (256 * SBOX32_MAX_LEN);