avcodec/Makefile: Fix mlpenc dependencies

Signed-off-by: James Almer <jamrial@gmail.com>

libavcodec/Makefile

@@ -383,7 +383,7 @@ OBJS-$(CONFIG_MJPEG_ENCODER)           += mjpegenc.o mjpegenc_common.o
 OBJS-$(CONFIG_MJPEGB_DECODER)          += mjpegbdec.o
 OBJS-$(CONFIG_MJPEG_VAAPI_ENCODER)     += vaapi_encode_mjpeg.o
 OBJS-$(CONFIG_MLP_DECODER)             += mlpdec.o mlpdsp.o
-OBJS-$(CONFIG_MLP_ENCODER)             += mlpenc.o
+OBJS-$(CONFIG_MLP_ENCODER)             += mlpenc.o mlp.o
 OBJS-$(CONFIG_MMVIDEO_DECODER)         += mmvideo.o
 OBJS-$(CONFIG_MOTIONPIXELS_DECODER)    += motionpixels.o
 OBJS-$(CONFIG_MOVTEXT_DECODER)         += movtextdec.o ass.o