multimedia/vapoursynth: unbreak after r503610

src/core/vsresize.cpp:88:20: error: use of undeclared identifier 'ZIMG_CPU_X86_AVX512_SKL'; did you mean 'ZIMG_CPU_X86_AVX512_SKX'?

{ "avx512skl", ZIMG_CPU_X86_AVX512_SKL },
               ^~~~~~~~~~~~~~~~~~~~~~~
               ZIMG_CPU_X86_AVX512_SKX

/usr/local/include/zimg.h:171:2: note: 'ZIMG_CPU_X86_AVX512_SKX' declared here

ZIMG_CPU_X86_AVX512_SKX = 1011  /**< AVX-512 {F,CD,VL,BW,DQ} (e.g. Skylake-X/SP). */
^

Reported by: pkg-fallout
Obtained from: upstream