dtrace: SDT cleanup and bring in line with kernel

dtrace: SDT cleanup and bring in line with kernel

This commit performs some cleanup on the SDT provider, removing some
housekeeping tasks that are no longer needed (such as the need for an
arch-specific sdt_provide_module_arch() function).

This commit also contains a fix for the loop used in enabling and
disabling probes.  It was failing to ensure that the enable/disable
function was being called with the correct SDT probe.

Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>