Fix --disable-everything

Breakage was due to ff_find_pix_fmt() usage.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/Makefile

@@ -18,6 +18,7 @@ OBJS = allcodecs.o                                                      \
        options.o                                                        \
        parser.o                                                         \
        raw.o                                                            \
+       rawdec.o                                                         \
        resample.o                                                       \
        resample2.o                                                      \
        simple_idct.o                                                    \