10l: Fix mistake in r26044. Check increment bounds using actual increment

instead of 64. This will change output in some cases, but it happens to not
affect the AC-3 regression tests.

Originally committed as revision 26180 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/ac3enc.c

@@ -1125,7 +1125,7 @@ static int cbr_bit_allocation(AC3EncodeContext *s)
 
     FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
     for (snr_incr = 64; snr_incr > 0; snr_incr >>= 2) {
-        while (snr_offset + 64 <= 1023 &&
+        while (snr_offset + snr_incr <= 1023 &&
                bit_alloc(s, snr_offset + snr_incr) <= bits_left) {
             snr_offset += snr_incr;
             FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);