PM / Runtime: GENERIC_SUBSYS_PM_OPS is gone

Update the documentation for the removal of GENERIC_SUBSYS_PM_OPS in commit
90363dd ("PM: Drop generic_subsys_pm_ops")

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation/power/runtime_pm.txt

@@ -727,15 +727,12 @@ driver/base/power/generic_ops.c:
   int pm_generic_restore_noirq(struct device *dev);
     - invoke the ->restore_noirq() callback provided by the device's driver
 
-These functions can be assigned to the ->runtime_idle(), ->runtime_suspend(),
+These functions are the defaults used by the PM core, if a subsystem doesn't
+provide its own callbacks for ->runtime_idle(), ->runtime_suspend(),
 ->runtime_resume(), ->suspend(), ->suspend_noirq(), ->resume(),
 ->resume_noirq(), ->freeze(), ->freeze_noirq(), ->thaw(), ->thaw_noirq(),
-->poweroff(), ->poweroff_noirq(), ->restore(), ->restore_noirq() callback
-pointers in the subsystem-level dev_pm_ops structures.
-
-If a subsystem wishes to use all of them at the same time, it can simply assign
-the GENERIC_SUBSYS_PM_OPS macro, defined in include/linux/pm.h, to its
-dev_pm_ops structure pointer.
+->poweroff(), ->poweroff_noirq(), ->restore(), ->restore_noirq() in the
+subsystem-level dev_pm_ops structure.
 
 Device drivers that wish to use the same function as a system suspend, freeze,
 poweroff and runtime suspend callback, and similarly for system resume, thaw,