avcodec/mpegaudiodec_template: use double to build csa tables

Fixes rounding difference between 32bit x86 and 64bit
Fixes fate failure with gapless mp3
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/mpegaudiodec_template.c

@@ -388,7 +388,7 @@ static av_cold void decode_init_static(void)
     }
 
     for (i = 0; i < 8; i++) {
-        float ci, cs, ca;
+        double ci, cs, ca;
         ci = ci_table[i];
         cs = 1.0 / sqrt(1.0 + ci * ci);
         ca = cs * ci;

tests/ref/fate/gapless-mp3

 d5c88cf38416329a052a9b0cb140fb4c *tests/data/fate/gapless-mp3.out-1
-3e41cbd4dcd511d3155234684252beab
+c96c3ae7bd3300fd2f4debac222de5b7
 68f040b12d79c71e3b2e8ba90a9cbd96 *tests/data/fate/gapless-mp3.out-2
-3e41cbd4dcd511d3155234684252beab
\ No newline at end of file
+c96c3ae7bd3300fd2f4debac222de5b7