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/ARM/ARMInstrInfo.h b/llvm/lib/Target/ARM/ARMInstrInfo.h
index 7f13d03..94ade3b 100644
--- a/llvm/lib/Target/ARM/ARMInstrInfo.h
+++ b/llvm/lib/Target/ARM/ARMInstrInfo.h
@@ -11,8 +11,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef ARMINSTRUCTIONINFO_H
-#define ARMINSTRUCTIONINFO_H
+#ifndef LLVM_LIB_TARGET_ARM_ARMINSTRINFO_H
+#define LLVM_LIB_TARGET_ARM_ARMINSTRINFO_H
 
 #include "ARMBaseInstrInfo.h"
 #include "ARMRegisterInfo.h"