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 c3ca90a92e7211aef8ad1d044518a34f6ba137d7)
diff --git a/libavcodec/x86/vp3dsp_init.c b/libavcodec/x86/vp3dsp_init.c
index ba47e1c..d23420c 100644
--- a/libavcodec/x86/vp3dsp_init.c
+++ b/libavcodec/x86/vp3dsp_init.c
@@ -60,7 +60,7 @@
 
         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;
         }
     }