memory: tegra30: Fix build error w/o PM

Make this depend on CONFIG_PM.
Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com>
Reviewed-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Stephen Warren <swarren@nvidia.com>

drivers/memory/tegra30-mc.c

@@ -268,6 +268,7 @@ static const u32 tegra30_mc_ctx[] = {
 	MC_INTMASK,
 };
 
+#ifdef CONFIG_PM
 static int tegra30_mc_suspend(struct device *dev)
 {
 	int i;
@@ -291,6 +292,7 @@ static int tegra30_mc_resume(struct device *dev)
 	mc_readl(mc, MC_TIMING_CONTROL);
 	return 0;
 }
+#endif
 
 static UNIVERSAL_DEV_PM_OPS(tegra30_mc_pm,
 			    tegra30_mc_suspend,