[Hexagon] Standardize next batch of pseudo instructions

ALIGNA          PS_aligna
ALLOCA          PS_alloca
TFR_FI          PS_fi
TFR_FIA         PS_fia
TFR_PdFalse     PS_false
TFR_PdTrue      PS_true
VMULW           PS_vmulw
VMULW_ACC       PS_vmulw_acc

llvm-svn: 278832