libSceVdecsw technical debt

libSceVdecsw (libSceVdecsw) - structure layouts follow shadPS4's vdecsw.h and were checked against PPSA05684's movie decoder (movie-decoder-vdecsw.cpp), which asserts pictureCount == 1 at offset 0xb of OutputInfo and reads InputResult offset 0x10 as the number of frames an access unit produced. The compute, decoder memory and decode input structures and the first 0x28 bytes of the 0x50-byte decoder config are those of libSceVideodec2, and decoding goes through it. The 0x78-byte AVC picture info is filled with Videodec2's leading fields and the cropping fields only. OUTPUT_PENDING (0x81510115), INPUT_QUEUE_EMPTY (0x81510116) and DECODE_PENDING (0x81510117) follow from the codes each call's assert accepts. At most four decoded pictures are queued and the last one is held until sceVdecswFinalizeDecodeSequence; the console's queue depth is unknown