[VE] Disable automatic maxnum/minnum selection

Disable FMAX/FMIN selection from select_cc in VEInstrInfo.td because of
the lack of NaN consideration.  This patch removes such selection from
VEInstrInfo.td and lets llvm work on it in combineMinNumMaxNum.

Reviewed By: efocht

Differential Revision: https://reviews.llvm.org/D134595