Consistently say va_arg rather than __va_arg.

Bug: http://b/64250392
Test: builds
Change-Id: I435242f620245d825b8a68365c71c99a60aba625
diff --git a/libc/stdio/local.h b/libc/stdio/local.h
index 1697116..6fb2c0d 100644
--- a/libc/stdio/local.h
+++ b/libc/stdio/local.h
@@ -201,10 +201,10 @@
 int	__swhatbuf(FILE *, size_t *, int *);
 wint_t __fgetwc_unlock(FILE *);
 wint_t	__ungetwc(wint_t, FILE *);
-int	__vfprintf(FILE *, const char *, __va_list);
-int	__svfscanf(FILE *, const char *, __va_list);
-int	__vfwprintf(FILE *, const wchar_t *, __va_list);
-int	__vfwscanf(FILE *, const wchar_t *, __va_list);
+int	__vfprintf(FILE *, const char *, va_list);
+int	__svfscanf(FILE *, const char *, va_list);
+int	__vfwprintf(FILE *, const wchar_t *, va_list);
+int	__vfwscanf(FILE *, const wchar_t *, va_list);
 
 /*
  * Return true if the given FILE cannot be written now.