configure: Add wmv2dsp->qpeldsp dependency

It reuses e.g. ff_put_pixels8_l2_8() directly even though
it never initializes a QpelDSPContext.
Fixes standalone compilation of the wmv2 encoder (the decoder
already has a qpeldsp dependency via the h263 decoder).

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

configure

@@ -2874,6 +2874,7 @@ mpegvideoenc_select="aandcttables fdctdsp me_cmp mpegvideo pixblockdsp"
 msmpeg4dec_select="h263_decoder"
 msmpeg4enc_select="h263_encoder"
 vc1dsp_select="h264chroma qpeldsp startcode"
+wmv2dsp_select="qpeldsp"
 
 # decoders / encoders
 aac_decoder_select="adts_header mpeg4audio sinewin"