clover/event: Include additional event statuses for clSetEventCallback

clover/event: Include additional event statuses for clSetEventCallback

From CL 2.0 Section 5.11 (Event Objects):
  clSetEventCallback returns CL_SUCCESS if the function is executed successfully. Otherwise, it
  returns one of the following errors:
    ...
    CL_INVALID_VALUE if pfn_event_notify is NULL or if command_exec_callback_type is
    not CL_SUBMITTED , CL_RUNNING or CL_COMPLETE .

Fixes: OpenCL CTS test_conformance/events/test_events callbacks
Signed-off-by: Aaron Watry <awatry@gmail.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>