[S390] mutex: enable spinning mutex on s390

This enables the spinning mutex feature on s390 by removing
HAVE_DEFAULT_NO_SPIN_MUTEXES from arch/s390/Kconfig.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/Kconfig

@@ -73,7 +73,6 @@ config S390
 	select HAVE_DYNAMIC_FTRACE
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_REGS_AND_STACK_ACCESS_API
-	select HAVE_DEFAULT_NO_SPIN_MUTEXES
 	select HAVE_OPROFILE
 	select HAVE_KPROBES
 	select HAVE_KRETPROBES