[Bug target/65744] Some AVX512 instrinsics take __mmask16 instead of __mmask8

[kyukhin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65744

--- Comment #2 from Kirill Yukhin <kyukhin at gcc dot gnu.org> ---
Created attachment 35306
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35306&action=edit
Proposed patch.

Conversion of decls of masked built-ins to make
masking unsigned (QI/HI->UQI/UHI) is a matter of
separate  patch.