[S390] Enable flexible mmap layout for 64 bit processes

Historically 64 bit processes use the legacy address layout. However
there is no reason why 64 bit processes shouldn't benefit from the
flexible mmap layout advantages.
Therefore just enable it.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/mm/mmap.c

@@ -61,16 +61,11 @@ static inline unsigned long mmap_base(void)
 
 static inline int mmap_is_legacy(void)
 {
-#ifdef CONFIG_64BIT
-	/*
-	 * Force standard allocation for 64 bit programs.
-	 */
-	if (!is_compat_task())
+	if (current->personality & ADDR_COMPAT_LAYOUT)
 		return 1;
-#endif
-	return sysctl_legacy_va_layout ||
-	    (current->personality & ADDR_COMPAT_LAYOUT) ||
-	    rlimit(RLIMIT_STACK) == RLIM_INFINITY;
+	if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
+		return 1;
+	return sysctl_legacy_va_layout;
 }
 
 #ifndef CONFIG_64BIT