[PATCH] s390: fix finish_arch_switch

Commit 4866cde0 requires finish_arch_switch
to have only one parameter instead of two.

Also fix another compile error (double declaration of account_system_vtime)
if CONFIG_VIRT_CPU_ACCOUNTING is not defined.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>