s390/cpum_cf: remove unneeded debug statements

Remove most debug statements which are not needed anymore from
the CPU Measurement counter facility device driver.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>