This patch makes sure that relaxed ordering is not disabled when
on SPARC, where it helps with performance.

CC: <kernel-team@fb.com>
CC: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Reported-by: NSowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>
Tested-by: NPhil Schmitt <phillip.j.schmitt@intel.com>