[RISCV][NFC] Make use of Triple::isRISCV

Use new helper introduced in rL365327.

llvm-svn: 365329
diff --git a/clang/lib/Driver/ToolChains/Gnu.cpp b/clang/lib/Driver/ToolChains/Gnu.cpp
index c852096..33cdd35 100644
--- a/clang/lib/Driver/ToolChains/Gnu.cpp
+++ b/clang/lib/Driver/ToolChains/Gnu.cpp
@@ -933,10 +933,6 @@
   return A && A->getOption().matches(options::OPT_mmicromips);
 }
 
-static bool isRISCV(llvm::Triple::ArchType Arch) {
-  return Arch == llvm::Triple::riscv32 || Arch == llvm::Triple::riscv64;
-}
-
 static bool isMSP430(llvm::Triple::ArchType Arch) {
   return Arch == llvm::Triple::msp430;
 }
@@ -2312,7 +2308,7 @@
   } else if (TargetTriple.isMIPS()) {
     if (!findMIPSMultilibs(D, TargetTriple, Path, Args, Detected))
       return false;
-  } else if (isRISCV(TargetArch)) {
+  } else if (TargetTriple.isRISCV()) {
     findRISCVMultilibs(D, TargetTriple, Path, Args, Detected);
   } else if (isMSP430(TargetArch)) {
     findMSP430Multilibs(D, TargetTriple, Path, Args, Detected);