lavfi/Makefile: Fix bwdif filter standalone compilation.

libavfilter/Makefile

@@ -167,7 +167,7 @@ OBJS-$(CONFIG_BM3D_FILTER)                   += vf_bm3d.o
 OBJS-$(CONFIG_BOXBLUR_FILTER)                += vf_boxblur.o boxblur.o
 OBJS-$(CONFIG_BOXBLUR_OPENCL_FILTER)         += vf_avgblur_opencl.o opencl.o \
                                                 opencl/avgblur.o boxblur.o
-OBJS-$(CONFIG_BWDIF_FILTER)                  += vf_bwdif.o
+OBJS-$(CONFIG_BWDIF_FILTER)                  += vf_bwdif.o yadif_common.o
 OBJS-$(CONFIG_CHROMAHOLD_FILTER)             += vf_chromakey.o
 OBJS-$(CONFIG_CHROMAKEY_FILTER)              += vf_chromakey.o
 OBJS-$(CONFIG_CHROMASHIFT_FILTER)            += vf_chromashift.o