staging: lustre: ptlrpc: Move IT_* definitions to lustre_idl.h

Put IT_* definitions into an enum, as they're sent over the wire,
adjust calls, print statements, etc. to use the new enum.

Signed-off-by: Ben Evans <bevans@cray.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6746
Reviewed-on: http://review.whamcloud.com/16228


Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>