Treat auto as a type

It is a type in C++. Let's treat it as such to avoid false-positive
spacing errors when processing C++ source files.

Author: locker

checkpatch.pl

@@ -608,6 +608,7 @@ sub find_standard_signature {
 );
 
 our @typeList = (
+	qr{auto},
 	qr{void},
 	qr{(?:(?:un)?signed\s+)?char},
 	qr{(?:(?:un)?signed\s+)?short\s+int},