s390/compat: fix compile error for !COMPAT

Fix this one for !COMPAT:

compat.h: In function ‘arch_compat_alloc_user_space’:
compat.h:292:2: error: implicit declaration of function ‘is_compat_task’
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/compat.h

@@ -248,8 +248,6 @@ static inline int is_compat_task(void)
 	return is_32bit_task();
 }
 
-#endif
-
 static inline void __user *arch_compat_alloc_user_space(long len)
 {
 	unsigned long stack;
@@ -260,6 +258,8 @@ static inline void __user *arch_compat_alloc_user_space(long len)
 	return (void __user *) (stack - len);
 }
 
+#endif
+
 struct compat_ipc64_perm {
 	compat_key_t key;
 	__compat_uid32_t uid;