dtrace: add support for sparc64 2of3

dtrace: add support for sparc64 2of3

This commit is the 2nd of 3 commits to add DTrace support to the sparc64
kernel.  This particular commit covers the generic kernel code changes.

The sparc64 implementation for SDT probe points utilizes a call to a
trampoline function that in turn calls dtrace_probe() rather than using
a trap-based mechanism.  This requires an additional data item to be
associated with each module.  In order to facilitate this in a manner that
is arch-dependent, DTrace specific data other than the list of SDT probes
has been moved to a structure that is maintained by the DTrace module code
and the module struct merely has a generic void *pdata member that can be
populated with a pointer to the actual data.

This commit also renames the num_dtrace_probes member of the module struct
to be sdt_probec, since that is more consistent.

Orabug: 19005031

Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>
Reviewed-by: Nick Alcock <nick.alcock@oracle.com>