PM / Documentation: suspend-and-cpuhotplug.txt: Fix typo

sysfs was expected in this context.

Signed-off-by: Marcos Paulo de Souza <[e-mail]>
Acked-by: Srivatsa S. Bhat <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

Documentation/power/suspend-and-cpuhotplug.txt

···
 
                                   Write 'mem' to
                                 /sys/power/state
-                                    syfs file
+                                    sysfs file
                                         |
                                         v
                                Acquire pm_mutex lock