Take out unnecessary header file from highbd_loopfilter_sse2

The dependency on vp9_loopfilter.h is not needed.

Change-Id: Ic0583c43d3d63f19cef06cf9d8e5c8031601be6a

vpx_dsp/x86/highbd_loopfilter_sse2.c

@@ -12,7 +12,6 @@
 
 #include "./vpx_dsp_rtcd.h"
 #include "vpx_ports/mem.h"
-#include "vp9/common/vp9_loopfilter.h"
 #include "vpx_ports/emmintrin_compat.h"
 
 static INLINE __m128i signed_char_clamp_bd_sse2(__m128i value, int bd) {