Add loopfilter initialization fix in multithreading code

Modified loopfilter initialization to avoid unnecessary operations.

Change-Id: I9fd1a5a49edc1cb8116c2a72a6908b1e437459ec
diff --git a/vp8/common/onyxc_int.h b/vp8/common/onyxc_int.h
index 4d5d987..33a5433 100644
--- a/vp8/common/onyxc_int.h
+++ b/vp8/common/onyxc_int.h
@@ -201,6 +201,7 @@
 
 void vp8_adjust_mb_lf_value(MACROBLOCKD *mbd, int *filter_level);
 void vp8_init_loop_filter(VP8_COMMON *cm);
+void vp8_frame_init_loop_filter(loop_filter_info *lfi, int frame_type);
 extern void vp8_loop_filter_frame(VP8_COMMON *cm,    MACROBLOCKD *mbd,  int filt_val);
 
 #endif