sse.md (VI248_AVX2_8_AVX512F): New.

sse.md (VI248_AVX2_8_AVX512F): New.

        * config/i386/sse.md (VI248_AVX2_8_AVX512F): New.
        (VI124_256): Changed to ...
        (VI124_256_48_512): This.
        (ssepackmode): Extended with wider modes.
        (<code><mode>3): Changed iterator.
        (*avx2_<code><mode>3): Ditto.
        (vec_pack_trunc_<mode>): Ditto.

Co-Authored-By: Andrey Turetskiy <andrey.turetskiy@intel.com>
Co-Authored-By: Anna Tikhonova <anna.tikhonova@intel.com>
Co-Authored-By: Ilya Tocar <ilya.tocar@intel.com>
Co-Authored-By: Ilya Verbin <ilya.verbin@intel.com>
Co-Authored-By: Kirill Yukhin <kirill.yukhin@intel.com>
Co-Authored-By: Maxim Kuznetsov <maxim.kuznetsov@intel.com>
Co-Authored-By: Michael Zolotukhin <michael.v.zolotukhin@intel.com>
Co-Authored-By: Sergey Lega <sergey.s.lega@intel.com>
From-SVN: r203437