s390/cpum_cf: provide counter number to validate_ctr_version()

Function validate_ctr_version() first parameter is a pointer to
a large structure, but only member hw_perf_event::config is used.
Supply this structure member value in the function invocation.

No functional change.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>