avfilter/Makefile: Add missing morpho->framesync dependency

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavfilter/Makefile

@@ -391,7 +391,7 @@ OBJS-$(CONFIG_MIDEQUALIZER_FILTER)           += vf_midequalizer.o framesync.o
 OBJS-$(CONFIG_MINTERPOLATE_FILTER)           += vf_minterpolate.o motion_estimation.o
 OBJS-$(CONFIG_MIX_FILTER)                    += vf_mix.o framesync.o
 OBJS-$(CONFIG_MONOCHROME_FILTER)             += vf_monochrome.o
-OBJS-$(CONFIG_MORPHO_FILTER)                 += vf_morpho.o
+OBJS-$(CONFIG_MORPHO_FILTER)                 += vf_morpho.o framesync.o
 OBJS-$(CONFIG_MPDECIMATE_FILTER)             += vf_mpdecimate.o
 OBJS-$(CONFIG_MULTIPLY_FILTER)               += vf_multiply.o framesync.o
 OBJS-$(CONFIG_NEGATE_FILTER)                 += vf_negate.o