vp8: Add ifdef guards around the sse2 loopfilter in the sse2slow branch too

This was missed in the the previous commit in 70a1c800.
Signed-off-by: Martin Storsjö <martin@martin.st>

libavcodec/x86/vp8dsp-init.c

@@ -389,11 +389,13 @@ av_cold void ff_vp8dsp_init_x86(VP8DSPContext* c)
 
         c->vp8_v_loop_filter_simple = ff_vp8_v_loop_filter_simple_sse2;
 
+#if ARCH_X86_64 || HAVE_ALIGNED_STACK
         c->vp8_v_loop_filter16y_inner = ff_vp8_v_loop_filter16y_inner_sse2;
         c->vp8_v_loop_filter8uv_inner = ff_vp8_v_loop_filter8uv_inner_sse2;
 
         c->vp8_v_loop_filter16y       = ff_vp8_v_loop_filter16y_mbedge_sse2;
         c->vp8_v_loop_filter8uv       = ff_vp8_v_loop_filter8uv_mbedge_sse2;
+#endif
     }
 
     if (mm_flags & AV_CPU_FLAG_SSE2) {