s390/pai: Prevent invalid event number for pai_crypto PMU

The pai_crypto PMU has to check the event number. It has to be in
the supported range. This is not the case, the lower limit is not
checked. Fix this and obey the lower limit.

Fixes: 39d62336 ("s390/pai: add support for cryptography counters")

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Suggested-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Reviewed-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>