s390/zcrypt: tracepoint definitions for zcrypt device driver.

s390/zcrypt: tracepoint definitions for zcrypt device driver.

This patch introduces tracepoint definitions and tracepoint
event invocations for the s390 zcrypt device.

Currently there are just two tracepoint events defined.
An s390_zcrypt_req request event occurs as soon as the
request is recognized by the zcrypt ioctl function. This
event may act as some kind of request-processing-starts-now
indication.
As late as possible within the zcrypt ioctl function there
occurs the s390_zcrypt_rep event which may act as the point
in time where the request has been processed by the kernel
and the result is about to be transferred back to userspace.
The glue which binds together request and reply event is the
ptr parameter, which is the local buffer address where the
request from userspace has been stored by the ioctl function.

The main purpose of this zcrypt tracepoint patch is to get
some data for performance measurements together with
information about the kind of request and on which card and
queue the request has been processed. It is not an ffdc
interface as there is already code in the zcrypt device
driver to serve the s390 debug feature interface.

Signed-off-by: Harald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>