Remove dspr2 loop filter files from vp9_common.mk

These files have been moved to vpx_dsp directory. Clean the
vp9_common make file accordingly.

Change-Id: I9b1e820376421c801f705157e60cc7a55487f469
diff --git a/vp9/vp9_common.mk b/vp9/vp9_common.mk
index 9e27257..1a9c3bd 100644
--- a/vp9/vp9_common.mk
+++ b/vp9/vp9_common.mk
@@ -118,13 +118,6 @@
 VP9_COMMON_SRCS-$(HAVE_DSPR2)  += common/mips/dspr2/vp9_itrans16_dspr2.c
 VP9_COMMON_SRCS-$(HAVE_DSPR2)  += common/mips/dspr2/vp9_itrans32_cols_dspr2.c
 VP9_COMMON_SRCS-$(HAVE_DSPR2)  += common/mips/dspr2/vp9_itrans32_dspr2.c
-VP9_COMMON_SRCS-$(HAVE_DSPR2)  += common/mips/dspr2/vp9_loopfilter_filters_dspr2.c
-VP9_COMMON_SRCS-$(HAVE_DSPR2)  += common/mips/dspr2/vp9_loopfilter_filters_dspr2.h
-VP9_COMMON_SRCS-$(HAVE_DSPR2)  += common/mips/dspr2/vp9_loopfilter_macros_dspr2.h
-VP9_COMMON_SRCS-$(HAVE_DSPR2)  += common/mips/dspr2/vp9_loopfilter_masks_dspr2.h
-VP9_COMMON_SRCS-$(HAVE_DSPR2)  += common/mips/dspr2/vp9_mbloop_loopfilter_dspr2.c
-VP9_COMMON_SRCS-$(HAVE_DSPR2)  += common/mips/dspr2/vp9_mblpf_horiz_loopfilter_dspr2.c
-VP9_COMMON_SRCS-$(HAVE_DSPR2)  += common/mips/dspr2/vp9_mblpf_vert_loopfilter_dspr2.c
 
 # common (msa)
 VP9_COMMON_SRCS-$(HAVE_MSA) += common/mips/msa/vp9_convolve8_avg_horiz_msa.c