s390/topology: Add config option to switch to vertical during boot

By default, all systems on s390 start in horizontal cpu polarization.
Selecting the new config option SCHED_TOPOLOGY_VERTICAL allows to build
a kernel that switches to vertical polarization during boot.

Acked-by: Heiko Carstens <hca@linux.ibm.com>
Tested-by: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Tobias Huschle <huschle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>