PM: hibernate: Fix hybrid-sleep

Hybrid sleep will hibernate the system followed by running through
the suspend routine.  Since both the hibernate and the suspend routine
will call pm_restrict_gfp_mask(), pm_restore_gfp_mask() must be called
before starting the suspend sequence.

Add an explicit call to pm_restore_gfp_mask() to power_down() before
the suspend sequence starts. Add an extra call for pm_restrict_gfp_mask()
when exiting suspend so that the pm_restore_gfp_mask() call in hibernate()
is balanced.

Reported-by: Ionut Nechita <ionut_n2001@yahoo.com>
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4573
Tested-by: Ionut Nechita <ionut_n2001@yahoo.com>
Fixes: 12ffc3b ("PM: Restrict swap use to later in the suspend sequence")
Tested-by: Kenneth Crudup <kenny@panix.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
Link: https://patch.msgid.link/20250925185108.2968494-2-superm1@kernel.org
[ rjw: Add comment explainig the new pm_restrict_gfp_mask() call purpose ]
Cc: 6.16+ <stable@vger.kernel.org> # 6.16+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: superm1

kernel/power/hibernate.c

@@ -695,12 +695,16 @@ static void power_down(void)
 
 #ifdef CONFIG_SUSPEND
 	if (hibernation_mode == HIBERNATION_SUSPEND) {
+		pm_restore_gfp_mask();
 		error = suspend_devices_and_enter(mem_sleep_current);
 		if (error) {
 			hibernation_mode = hibernation_ops ?
 						HIBERNATION_PLATFORM :
 						HIBERNATION_SHUTDOWN;
 		} else {
+			/* Match pm_restore_gfp_mask() call in hibernate() */
+			pm_restrict_gfp_mask();
+
 			/* Restore swap signature. */
 			error = swsusp_unmark();
 			if (error)