[PAL] Remove unused stdarg.h

Pal/include/stdarg.h

@@ -1,12 +0,0 @@
-#ifndef _STDARG_H_
-#define _STDARG_H_
-
-typedef __builtin_va_list va_list;
-
-#define va_start(ap, last) __builtin_va_start(ap, last)
-
-#define va_arg(ap, type) __builtin_va_arg(ap, type)
-
-#define va_end(ap) __builtin_va_end(ap)
-
-#endif  /* _STDARG_H_ */