tpm/tpm_crb: fix unused warnings on suspend/resume functions

When PM_SLEEP is disabled crb_pm_suspend and crb_pm_resume are not used by
SET_SYSTEM_SLEEP_PM_OPS even if PM is enabled:

drvers/char/tpm/tpm_crb.c:540:12: warning: ‘crb_pm_suspend’ defined but not
used [-Wunused-function]
 static int crb_pm_suspend(struct device *dev)
            ^
drivers/char/tpm/tpm_crb.c:551:12: warning: ‘crb_pm_resume’ defined but not
used [-Wunused-function]
 static int crb_pm_resume(struct device *dev)
            ^

The preprocessor condition should be on CONFIG_PM_SLEEP, not on CONFIG_PM.
However, this patch fixes this warning by using __maybe_unused on function
that are in the preprocessor condition.

Fixes: 848efcfb560c ("tpm/tpm_crb: enter the low power state upon device suspend")
Signed-off-by: Jérémy Lefaure <jeremy.lefaure@lse.epita.fr>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

drivers/char/tpm/tpm_crb.c

@@ -519,8 +519,7 @@ static int crb_acpi_remove(struct acpi_device *device)
 	return 0;
 }
 
-#ifdef CONFIG_PM
-static int crb_pm_runtime_suspend(struct device *dev)
+static int __maybe_unused crb_pm_runtime_suspend(struct device *dev)
 {
 	struct tpm_chip *chip = dev_get_drvdata(dev);
 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
@@ -528,7 +527,7 @@ static int crb_pm_runtime_suspend(struct device *dev)
 	return crb_go_idle(dev, priv);
 }
 
-static int crb_pm_runtime_resume(struct device *dev)
+static int __maybe_unused crb_pm_runtime_resume(struct device *dev)
 {
 	struct tpm_chip *chip = dev_get_drvdata(dev);
 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
@@ -536,7 +535,7 @@ static int crb_pm_runtime_resume(struct device *dev)
 	return crb_cmd_ready(dev, priv);
 }
 
-static int crb_pm_suspend(struct device *dev)
+static int __maybe_unused crb_pm_suspend(struct device *dev)
 {
 	int ret;
 
@@ -547,7 +546,7 @@ static int crb_pm_suspend(struct device *dev)
 	return crb_pm_runtime_suspend(dev);
 }
 
-static int crb_pm_resume(struct device *dev)
+static int __maybe_unused crb_pm_resume(struct device *dev)
 {
 	int ret;
 
@@ -558,8 +557,6 @@ static int crb_pm_resume(struct device *dev)
 	return tpm_pm_resume(dev);
 }
 
-#endif /* CONFIG_PM */
-
 static const struct dev_pm_ops crb_pm = {
 	SET_SYSTEM_SLEEP_PM_OPS(crb_pm_suspend, crb_pm_resume)
 	SET_RUNTIME_PM_OPS(crb_pm_runtime_suspend, crb_pm_runtime_resume, NULL)