aacsbr: add a assert0 to check for a inconsistency that

occurd during debug. I dont know if this can happen normally but if so
it would be quite bad.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/aacsbr.c

@@ -33,6 +33,7 @@
 #include "fft.h"
 #include "aacps.h"
 #include "libavutil/libm.h"
+#include "libavutil/avassert.h"
 
 #include <stdint.h>
 #include <float.h>
@@ -1457,6 +1458,7 @@ static void sbr_mapping(AACContext *ac, SpectralBandReplication *sbr,
         uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;
         int k;
 
+        av_assert0(sbr->kx[1] <= table[0]);
         for (i = 0; i < ilim; i++)
             for (m = table[i]; m < table[i + 1]; m++)
                 sbr->e_origmapped[e][m - sbr->kx[1]] = ch_data->env_facs[e+1][i];