avutil/md5: stop discarding the const qualifier for the src pointer

The code modifying the buffer on big endian systems was removed.
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: James Almer <jamrial@gmail.com>

libavutil/md5.c

@@ -98,11 +98,12 @@ static const uint32_t T[64] = { // T[i]= fabs(sin(i+1)<<32)
         a = b + (a << t | a >> (32 - t));                               \
     } while (0)
 
-static void body(uint32_t ABCD[4], uint32_t *src, int nblocks)
+static void body(uint32_t ABCD[4], const uint8_t *src, int nblocks)
 {
     int i av_unused;
     int n;
-    uint32_t a, b, c, d, t, *X;
+    const uint32_t *X;
+    uint32_t a, b, c, d, t;
 
     for (n = 0; n < nblocks; n++) {
         a = ABCD[3];
@@ -110,7 +111,7 @@ static void body(uint32_t ABCD[4], uint32_t *src, int nblocks)
         c = ABCD[1];
         d = ABCD[0];
 
-        X = src + n * 16;
+        X = (const uint32_t *)src + n * 16;
 
 #if CONFIG_SMALL
         for (i = 0; i < 64; i++) {
@@ -164,19 +165,19 @@ void av_md5_update(AVMD5 *ctx, const uint8_t *src, int len)
         len -= cnt;
         if (j + cnt < 64)
             return;
-        body(ctx->ABCD, (uint32_t *)ctx->block, 1);
+        body(ctx->ABCD, ctx->block, 1);
     }
 
     end = src + (len & ~63);
     if (!HAVE_FAST_UNALIGNED && ((intptr_t)src & 3)) {
        while (src < end) {
            memcpy(ctx->block, src, 64);
-           body(ctx->ABCD, (uint32_t *) ctx->block, 1);
+           body(ctx->ABCD, ctx->block, 1);
            src += 64;
         }
     } else {
         int nblocks = len / 64;
-        body(ctx->ABCD, (uint32_t *)src, nblocks);
+        body(ctx->ABCD, src, nblocks);
         src = end;
     }
     len &= 63;