[SKL][MPEG2ENC] MPEG2ENC lead to GPU hang in SKL

[mypopydev]

in SKL, mpeg2enc will hang when setting macro block address like this:

vslice->macroblock_address = priv->mb_width * slice->index;
vslice->num_macroblocks = priv->mb_width;

but when change the code as: vslice->macroblock_address =slice->index;, it's working, I think media-driver doesn't follow VA-API Spec for uint32_t macroblock_address in VAEncSliceParameterBufferMPEG2. (https://github.com/01org/libva/blob/c88000b75602ded8ec24e6ea032f4841a4437049/va/va_enc_mpeg2.h#L278)

[XinfengZhang]

will fix it.