avfilter/x86/vf_noise: Remove obsolete MMX function

x64 always has MMX, MMXEXT, SSE and SSE2 and this means
that some functions for MMX, MMXEXT and 3dnow are always
overridden by other functions (unless one e.g. explicitly
disables SSE2) for x64. So given that the only systems that
benefit from line_noise_mmx are truely ancient 32bit x86s
it is removed.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavfilter/x86/vf_noise.c

@@ -25,34 +25,6 @@
 #include "libavfilter/vf_noise.h"
 
 #if HAVE_INLINE_ASM
-static void line_noise_mmx(uint8_t *dst, const uint8_t *src,
-                           const int8_t *noise, int len, int shift)
-{
-    x86_reg mmx_len= len & (~7);
-    noise += shift;
-
-    __asm__ volatile(
-            "mov %3, %%"FF_REG_a"            \n\t"
-            "pcmpeqb %%mm7, %%mm7            \n\t"
-            "psllw $15, %%mm7                \n\t"
-            "packsswb %%mm7, %%mm7           \n\t"
-            ".p2align 4                      \n\t"
-            "1:                              \n\t"
-            "movq (%0, %%"FF_REG_a"), %%mm0  \n\t"
-            "movq (%1, %%"FF_REG_a"), %%mm1  \n\t"
-            "pxor %%mm7, %%mm0               \n\t"
-            "paddsb %%mm1, %%mm0             \n\t"
-            "pxor %%mm7, %%mm0               \n\t"
-            "movq %%mm0, (%2, %%"FF_REG_a")  \n\t"
-            "add $8, %%"FF_REG_a"            \n\t"
-            " js 1b                          \n\t"
-            :: "r" (src+mmx_len), "r" (noise+mmx_len), "r" (dst+mmx_len), "g" (-mmx_len)
-            : "%"FF_REG_a
-    );
-    if (mmx_len != len)
-        ff_line_noise_c(dst+mmx_len, src+mmx_len, noise+mmx_len, len-mmx_len, 0);
-}
-
 #if HAVE_6REGS
 static void line_noise_avg_mmx(uint8_t *dst, const uint8_t *src,
                                       int len, const int8_t * const *shift)
@@ -132,7 +104,6 @@ av_cold void ff_noise_init_x86(NoiseContext *n)
     int cpu_flags = av_get_cpu_flags();
 
     if (INLINE_MMX(cpu_flags)) {
-        n->line_noise     = line_noise_mmx;
 #if HAVE_6REGS
         n->line_noise_avg = line_noise_avg_mmx;
 #endif