build: Let AMV decoder depend on the SP5X decoder

This codec compiles all of the SP5X code anyway, so there is little
point in not enabling the decoder directly. This also simplifies the
dependency declaration for the AMV decoder.

configure

@@ -1638,7 +1638,7 @@ alac_encoder_select="lpc"
 als_decoder_select="dsputil"
 amrnb_decoder_select="lsp"
 amrwb_decoder_select="lsp"
-amv_decoder_select="dsputil hpeldsp"
+amv_decoder_select="sp5x_decoder"
 ape_decoder_select="dsputil"
 asv1_decoder_select="dsputil"
 asv1_encoder_select="dsputil"

libavcodec/Makefile

@@ -96,7 +96,6 @@ OBJS-$(CONFIG_AMRWB_DECODER)           += amrwbdec.o celp_filters.o   \
                                           celp_math.o acelp_filters.o \
                                           acelp_vectors.o             \
                                           acelp_pitch_delay.o
-OBJS-$(CONFIG_AMV_DECODER)             += sp5xdec.o mjpegdec.o mjpeg.o
 OBJS-$(CONFIG_ANM_DECODER)             += anm.o
 OBJS-$(CONFIG_ANSI_DECODER)            += ansi.o cga_data.o
 OBJS-$(CONFIG_APE_DECODER)             += apedec.o