[Hexagon] Add an option to use fast FP to int convert for some HVX cases (#169562)
Lowering several flavors of fptosi for HVX can be done faster, but
violates c/c++ convention on some arch tags. Nevertheless customers are
using direct intrinsics with "incorrect" rounding mode and want compiler
to do the same.
Default behavior is not changed.
Patch By: Fateme Hosseini
Co-authored-by: Sergei Larin <slarin@codeaurora.org>
Co-authored-by: Sergei Larin <slarin@qti.qualcomm.com>