Remove reference implementation of keccak

Replace with an import of fips202/keccakf1600.c

Author: bremoran

mldsa/fips202/keccakf1600.c

@@ -39,18 +39,18 @@
 void mld_keccakf1600_extract_bytes(uint64_t *state, unsigned char *data,
                                    unsigned offset, unsigned length)
 {
-  unsigned i;
 #if defined(MLD_USE_FIPS202_X1_NATIVE)
-  (void) i;
   mld_keccakf1600_extract_bytes_native(state, data, offset, length);
 #elif defined(MLD_SYS_LITTLE_ENDIAN)
+  unsigned i;
   uint8_t *state_ptr = (uint8_t *)state + offset;
   for (i = 0; i < length; i++)
   __loop__(invariant(i <= length))
   {
     data[i] = state_ptr[i];
   }
 #else  /* MLD_SYS_LITTLE_ENDIAN */
+  unsigned i;
   /* Portable version */
   for (i = 0; i < length; i++)
   __loop__(invariant(i <= length))
@@ -63,18 +63,18 @@ void mld_keccakf1600_extract_bytes(uint64_t *state, unsigned char *data,
 void mld_keccakf1600_xor_bytes(uint64_t *state, const unsigned char *data,
                                unsigned offset, unsigned length)
 {
-  unsigned i;
 #if defined(MLD_USE_FIPS202_X1_NATIVE)
-  (void) i;
   mld_keccakf1600_xor_bytes_native(state, data, offset, length);
 #elif defined(MLD_SYS_LITTLE_ENDIAN)
+  unsigned i;
   uint8_t *state_ptr = (uint8_t *)state + offset;
   for (i = 0; i < length; i++)
   __loop__(invariant(i <= length))
   {
     state_ptr[i] ^= data[i];
   }
 #else  /* MLD_SYS_LITTLE_ENDIAN */
+  unsigned i;
   /* Portable version */
   for (i = 0; i < length; i++)
   __loop__(invariant(i <= length))