configure: add forgotten avcodec/avformat deps for find/cover_rect

Found-by: ubitux
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

configure

@@ -2635,7 +2635,7 @@ blackframe_filter_deps="gpl"
 boxblur_filter_deps="gpl"
 bs2b_filter_deps="libbs2b"
 colormatrix_filter_deps="gpl"
-cover_rect_filter_deps="gpl"
+cover_rect_filter_deps="avcodec avformat gpl"
 cropdetect_filter_deps="gpl"
 delogo_filter_deps="gpl"
 deshake_filter_select="pixelutils"
@@ -2645,7 +2645,7 @@ eq_filter_deps="gpl"
 fftfilt_filter_deps="avcodec"
 fftfilt_filter_select="rdft"
 flite_filter_deps="libflite"
-find_rect_filter_deps="gpl"
+find_rect_filter_deps="avcodec avformat gpl"
 frei0r_filter_deps="frei0r dlopen"
 frei0r_src_filter_deps="frei0r dlopen"
 fspp_filter_deps="gpl"