PM: hibernate: Restrict GFP mask in power_down()

Commit 12ffc3b1 ("PM: Restrict swap use to later in the
suspend sequence") caused hibernation_platform_enter() to call
pm_restore_gfp_mask() via dpm_resume_end(), so when power_down()
returns after aborting hibernation_platform_enter(), it needs
to match the pm_restore_gfp_mask() call in hibernate() that will
occur subsequently.

Address this by adding a pm_restrict_gfp_mask() call to the relevant
error path in power_down().

Fixes: 12ffc3b1 ("PM: Restrict swap use to later in the suspend sequence")
Cc: 6.16+ <stable@vger.kernel.org> # 6.16+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>