configure: MMAL-related decoders should depend on, not select, mmal

configure

@@ -2136,7 +2136,6 @@ h264_d3d11va_hwaccel_select="h264_decoder"
 h264_dxva2_hwaccel_deps="dxva2"
 h264_dxva2_hwaccel_select="h264_decoder"
 h264_mmal_decoder_deps="mmal"
-h264_mmal_decoder_select="mmal"
 h264_mmal_hwaccel_deps="mmal"
 h264_omx_encoder_deps="omx"
 h264_qsv_hwaccel_deps="libmfx"
@@ -2164,7 +2163,6 @@ mpeg2_d3d11va_hwaccel_select="mpeg2video_decoder"
 mpeg2_dxva2_hwaccel_deps="dxva2"
 mpeg2_dxva2_hwaccel_select="mpeg2video_decoder"
 mpeg2_mmal_decoder_deps="mmal"
-mpeg2_mmal_decoder_select="mmal"
 mpeg2_mmal_hwaccel_deps="mmal"
 mpeg2_qsv_hwaccel_deps="libmfx"
 mpeg2_vaapi_hwaccel_deps="vaapi"
@@ -2181,7 +2179,6 @@ vc1_d3d11va_hwaccel_select="vc1_decoder"
 vc1_dxva2_hwaccel_deps="dxva2"
 vc1_dxva2_hwaccel_select="vc1_decoder"
 vc1_mmal_decoder_deps="mmal"
-vc1_mmal_decoder_select="mmal"
 vc1_mmal_hwaccel_deps="mmal"
 vc1_qsv_hwaccel_deps="libmfx"
 vc1_vaapi_hwaccel_deps="vaapi"