[RISCV] Reset NoPHIS MachineFunctionProperty in emitSelectPseudo

We insered PHIS were there were none before, so the property must be
reset. This error was found on an EXPENSIVE_CHECKS build.

llvm-svn: 366412
diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 5d8a2b0..ce7b859 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -1308,6 +1308,7 @@
     SelectMBBI = Next;
   }
 
+  F->getProperties().reset(MachineFunctionProperties::Property::NoPHIs);
   return TailMBB;
 }