Canonicalize header guards into a common format.

Add header guards to files that were missing guards. Remove #endif comments
as they don't seem common in LLVM (we can easily add them back if we decide
they're useful)

Changes made by clang-tidy with minor tweaks.

llvm-svn: 215558
diff --git a/llvm/lib/Target/Mips/MipsModuleISelDAGToDAG.h b/llvm/lib/Target/Mips/MipsModuleISelDAGToDAG.h
index f7a0310..85bae47 100644
--- a/llvm/lib/Target/Mips/MipsModuleISelDAGToDAG.h
+++ b/llvm/lib/Target/Mips/MipsModuleISelDAGToDAG.h
@@ -12,8 +12,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef MIPSMODULEISELDAGTODAG_H
-#define MIPSMODULEISELDAGTODAG_H
+#ifndef LLVM_LIB_TARGET_MIPS_MIPSMODULEISELDAGTODAG_H
+#define LLVM_LIB_TARGET_MIPS_MIPSMODULEISELDAGTODAG_H
 
 #include "Mips.h"
 #include "MipsSubtarget.h"