PM / Suspend: Fix bug in suspend statistics update

PM / Suspend: Fix bug in suspend statistics update

After commit c50f845af4c1f391f8e93fc05bf49181f1f8b07a
(PM / Suspend: Add statistics debugfs file for suspend to RAM)
a missing pair of braces inside the state_store() function causes even
invalid arguments to suspend to be wrongly treated as failed suspend
attempts. Fix this.

[rjw: Put the hash/subject of the buggy commit into the changelog.]

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>