remove i386 support for legacy struct __va_list

commit ffaaa6d2 removed the
corresponding stdarg.h support for compilers without va_list builtins,
but failed to remove the alternate type definition, leaving incorrect
va_list definitions in place with compilers that don't define __GNUC__
with a value >= 3.

arch/i386/bits/alltypes.h.in

@@ -2,13 +2,8 @@
 #define _Int64 long long
 #define _Reg int
 
-#if __GNUC__ >= 3
 TYPEDEF __builtin_va_list va_list;
 TYPEDEF __builtin_va_list __isoc_va_list;
-#else
-TYPEDEF struct __va_list * va_list;
-TYPEDEF struct __va_list * __isoc_va_list;
-#endif
 
 #ifndef __cplusplus
 #ifdef __WCHAR_TYPE__