s390/spinlock: optimize spinlock code sequence

Use lowcore constant to improve the code generated for spinlocks.

[ Martin Schwidefsky: patch breakdown and code beautification ]

Signed-off-by: Philipp Hachtmann <phacht@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --cc arch/s390/include/asm/lowcore.h
Simple merge

diff --cc arch/s390/include/asm/spinlock.h
Simple merge

diff --cc arch/s390/kernel/setup.c
Simple merge

diff --cc arch/s390/kernel/smp.c
Simple merge

diff --cc arch/s390/lib/spinlock.c
Simple merge