The key member of the runtime instrumentation control block contains
only the access key, not the complete storage key. Therefore the value
must be shifted by four bits.
Note: this is only relevant for debugging purposes in case somebody
compiles a kernel with a default storage access key set to a value not
equal to zero.

Fixes: e4b8b3f3 ("s390: add support for runtime instrumentation")
Reported-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>