video-converter: Mixing fields when converting chroma planes for various formats in interlaced mode

Submitted by Sebastian Dröge @slomo

Link to original bug (#777147)

Description

Missing in:
convert_I420_pack_ARGB
convert_I420_ARGB
convert_I420_BGRA
convert_AYUV_I420

Implemented in:
convert_UYVY_I420
convert_YUY2_I420
convert_I420_AYUV
convert_I420_UYVY
convert_I420_YUY2

Problem is that for interlaced mode it has to map chroma lines 0 and 2 to chroma line 1 (or the other way around), but currently uses lines 0 and 1.