avcodec/aacsbr_fixed: Fix multiple runtime error: shift exponent 170 is too...

avcodec/aacsbr_fixed: Fix multiple runtime error: shift exponent 170 is too large for 32-bit type 'int'

Fixes part of 1709/clusterfuzz-testcase-minimized-4513580554649600

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpegSigned-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/aacsbr_fixed.c

@@ -576,21 +576,26 @@ static void sbr_hf_assemble(int Y1[38][64][2],
                 SoftFloat *in  = sbr->s_m[e];
                 for (m = 0; m+1 < m_max; m+=2) {
                     shift = 22 - in[m  ].exp;
+                    if (shift < 32) {
                         round = 1 << (shift-1);
                         out[2*m  ] += (in[m  ].mant * A + round) >> shift;
+                    }
 
                     shift = 22 - in[m+1].exp;
+                    if (shift < 32) {
                         round = 1 << (shift-1);
                         out[2*m+2] += (in[m+1].mant * B + round) >> shift;
                     }
+                }
                 if(m_max&1)
                 {
                     shift = 22 - in[m  ].exp;
+                    if (shift < 32) {
                         round = 1 << (shift-1);
-
                         out[2*m  ] += (in[m  ].mant * A + round) >> shift;
                     }
                 }
+            }
             indexnoise = (indexnoise + m_max) & 0x1ff;
             indexsine = (indexsine + 1) & 3;
         }