fft: x86: cosmetics: Drop silly comments, add comment, whitespace

libavcodec/x86/fft_init.c

@@ -17,9 +17,11 @@
  */
 
 #include "config.h"
+
 #include "libavutil/attributes.h"
 #include "libavutil/cpu.h"
 #include "libavutil/x86/cpu.h"
+
 #include "fft.h"
 
 av_cold void ff_fft_init_x86(FFTContext *s)
@@ -28,28 +30,27 @@ av_cold void ff_fft_init_x86(FFTContext *s)
 
 #if ARCH_X86_32
     if (EXTERNAL_AMD3DNOW(cpu_flags)) {
-        /* 3DNow! for K6-2/3 */
         s->imdct_calc = ff_imdct_calc_3dnow;
         s->imdct_half = ff_imdct_half_3dnow;
         s->fft_calc   = ff_fft_calc_3dnow;
     }
+
     if (EXTERNAL_AMD3DNOWEXT(cpu_flags)) {
-        /* 3DNowEx for K7 */
         s->imdct_calc = ff_imdct_calc_3dnowext;
         s->imdct_half = ff_imdct_half_3dnowext;
         s->fft_calc   = ff_fft_calc_3dnowext;
     }
-#endif
+#endif /* ARCH_X86_32 */
+
     if (EXTERNAL_SSE(cpu_flags)) {
-        /* SSE for P3/P4/K8 */
         s->imdct_calc  = ff_imdct_calc_sse;
         s->imdct_half  = ff_imdct_half_sse;
         s->fft_permute = ff_fft_permute_sse;
         s->fft_calc    = ff_fft_calc_sse;
         s->fft_permutation = FF_FFT_PERM_SWAP_LSBS;
     }
+
     if (EXTERNAL_AVX_FAST(cpu_flags) && s->nbits >= 5) {
-        /* AVX for SB */
         s->imdct_half      = ff_imdct_half_avx;
         s->fft_calc        = ff_fft_calc_avx;
         s->fft_permutation = FF_FFT_PERM_AVX;