[mips] Correct label prefixes for N32 and N64.

Summary:
N32 and N64 follow the standard ELF conventions (.L) whereas O32 uses its own
($).

This fixes the majority of object differences between -fintegrated-as and
-fno-integrated-as.

Reviewers: sdardis

Subscribers: dsanders, sdardis, llvm-commits

Differential Revision: https://reviews.llvm.org/D22412

llvm-svn: 275967
diff --git a/llvm/lib/Target/Mips/MipsTargetMachine.cpp b/llvm/lib/Target/Mips/MipsTargetMachine.cpp
index c248c3a..80641ed 100644
--- a/llvm/lib/Target/Mips/MipsTargetMachine.cpp
+++ b/llvm/lib/Target/Mips/MipsTargetMachine.cpp
@@ -57,7 +57,10 @@
   else
     Ret += "E";
 
-  Ret += "-m:m";
+  if (ABI.IsO32())
+    Ret += "-m:m";
+  else
+    Ret += "-m:e";
 
   // Pointers are 32 bit on some ABIs.
   if (!ABI.IsN64())