From: Martin Schwidefsky <schwidefsky@de.ibm.com>

s390 core changes:
 - Move setting/clearing of TIF_31BIT thread flag to SET_PERSONALITY.
 - Use TASK_UNMAPPED_BASE in elf_map32 for mmaps with address 0.
 - Define ARCH_KMALLOC_MINALIGN.
 - Define ARCH_MIN_TASKALIGN.