[PATCH v2 -next] platform: surface: fix non-PM_SLEEP build warnings

[Randy Dunlap <rdunlap@xxxxxxxxxxxxx>]

Fix build warnings when CONFIG_PM_SLEEP is not enabled and these
functions are not used:

../drivers/platform/surface/surface_gpe.c:189:12: warning: ‘surface_gpe_resume’ defined but not used [-Wunused-function]
 static int surface_gpe_resume(struct device *dev)
            ^~~~~~~~~~~~~~~~~~
../drivers/platform/surface/surface_gpe.c:184:12: warning: ‘surface_gpe_suspend’ defined but not used [-Wunused-function]
 static int surface_gpe_suspend(struct device *dev)
            ^~~~~~~~~~~~~~~~~~~

Fixes: 274335f1c557 ("platform/surface: Add Driver to set up lid GPEs on MS Surface device")
Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Maximilian Luz <luzmaximilian@xxxxxxxxx>
Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
Cc: platform-driver-x86@xxxxxxxxxxxxxxx
---
v2: dropped Maximilian's RVB tag since the patch changed
    use preferred __maybe_unused instead of ifdeffery:
      https://lore.kernel.org/patchwork/patch/732981/

 drivers/platform/surface/surface_gpe.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- linux-next-20201214.orig/drivers/platform/surface/surface_gpe.c
+++ linux-next-20201214/drivers/platform/surface/surface_gpe.c
@@ -181,12 +181,12 @@ static int surface_lid_enable_wakeup(str
 	return 0;
 }
 
-static int surface_gpe_suspend(struct device *dev)
+static int __maybe_unused surface_gpe_suspend(struct device *dev)
 {
 	return surface_lid_enable_wakeup(dev, true);
 }
 
-static int surface_gpe_resume(struct device *dev)
+static int __maybe_unused surface_gpe_resume(struct device *dev)
 {
 	return surface_lid_enable_wakeup(dev, false);
 }