Remove redundant mm_flags declaration, fixes the warning:

libavcodec.a(dsputil_ppc.o): warning: definition of `mm_flags' overriding common
fft-test.o: warning: common is here

Originally committed as revision 13940 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/fft-test.c

@@ -33,8 +33,6 @@
 #undef exit
 #undef random
 
-int mm_flags;
-
 /* reference fft */
 
 #define MUL16(a,b) ((a) * (b))