avcodec/x86/vp3dsp_init: Set correct function pointer, fix crash

Regression since fd172185580c1ccdcfb90bbfdb59fa806fad3117;
triggered by vp4/KTkvw8dg1J8.avi in the FATE suite, but not
when running fate as this code is not used when the bitexact
flag is set.

Bisecting done by ami_stuff, patch from user Mika Fischer
in ticket #10027 (which this commit fixes).

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
(cherry picked from commit c3ca90a92e)

libavcodec/x86/vp3dsp_init.c

@@ -53,7 +53,7 @@ av_cold void ff_vp3dsp_init_x86(VP3DSPContext *c, int flags)
 
         if (!(flags & AV_CODEC_FLAG_BITEXACT)) {
             c->v_loop_filter = c->v_loop_filter_unaligned = ff_vp3_v_loop_filter_mmxext;
-            c->h_loop_filter = c->v_loop_filter_unaligned = ff_vp3_h_loop_filter_mmxext;
+            c->h_loop_filter = c->h_loop_filter_unaligned = ff_vp3_h_loop_filter_mmxext;
         }
     }