s390/mm: make TASK_SIZE independent from the number of page table levels

The TASK_SIZE for a process should be maximum possible size of the address
space, 2GB for a 31-bit process and 8PB for a 64-bit process. The number
of page table levels required for a given memory layout is a consequence
of the mapped memory areas and their location.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/mm/gmap.c

@@ -431,7 +431,7 @@ int gmap_map_segment(struct gmap *gmap, unsigned long from,
 	if ((from | to | len) & (PMD_SIZE - 1))
 		return -EINVAL;
 	if (len == 0 || from + len < from || to + len < to ||
-	    from + len - 1 > TASK_MAX_SIZE || to + len - 1 > gmap->asce_end)
+	    from + len - 1 > TASK_SIZE_MAX || to + len - 1 > gmap->asce_end)
 		return -EINVAL;
 
 	flush = 0;