ARM: tegra: tegra_powergate_is_powered should be static

Not exported and not used externally.

Also, fix return type. Due to new return type, errors can't be returned
so WARN_ON instead of returning error if a bad parameter is specified.

Signed-off-by: Olof Johansson <olof@lixom.net>
Acked-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/mach-tegra/powergate.c

@@ -89,12 +89,11 @@ int tegra_powergate_power_off(int id)
 	return tegra_powergate_set(id, false);
 }
 
-bool tegra_powergate_is_powered(int id)
+static bool tegra_powergate_is_powered(int id)
 {
 	u32 status;
 
-	if (id < 0 || id >= TEGRA_NUM_POWERGATE)
-		return -EINVAL;
+	WARN_ON(id < 0 || id >= TEGRA_NUM_POWERGATE);
 
 	status = pmc_read(PWRGATE_STATUS) & (1 << id);
 	return !!status;