desc_81: Fix compilation with older compilers

The attached fixes the following error when compiling 'dvblastctl'

  /usr/local/include/bitstream/atsc/si/desc_81.h: In function ‘desc81_bit_rate_code_from_octetrate’:
  /usr/local/include/bitstream/atsc/si/desc_81.h:83:5: error: ‘for’ loop initial declarations are only allowed in C99 mode
  /usr/local/include/bitstream/atsc/si/desc_81.h:83:5: note: use option -std=c99 or -std=gnu99 to compile your code

Apply via 'git am 0001-desc_81-Fix-compilation-with-older-compilers.patch'

atsc/si/desc_81.h

@@ -80,7 +80,8 @@ static inline uint8_t desc81_bit_rate_code_from_octetrate(uint64_t octetrate)
         256, 320, 384, 448, 512, 576,
         640,
     };
-    for (unsigned i = 0; i < 19; i++) {
+    unsigned i;
+    for (i = 0; i < 19; i++) {
         if (octetrate * 8 == table[i] * 1000)
             return i;
         else if (octetrate * 8 < table[i] * 1000)