[S390] Fix vmalloc area size calculation.

setup_memory_end() uses VMALLOC_END instead of VMALLOC_END_INIT to
calculate the maximum supported size of physical memory. Since
VMALLOC_END is zero, this will cause a crash on 31 bit systems.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/setup.c

@@ -476,7 +476,7 @@ static void __init setup_memory_end(void)
 	int i;
 
 	memory_size = real_size = 0;
-	max_phys = VMALLOC_END - VMALLOC_MIN_SIZE;
+	max_phys = VMALLOC_END_INIT - VMALLOC_MIN_SIZE;
 	memory_end &= PAGE_MASK;
 
 	max_mem = memory_end ? min(max_phys, memory_end) : max_phys;