soc/tegra: pmc: Ensure powergate is available when powering on

The function tegra_power_sequence_power_up() is a public function used
to power on a partition. When this function is called, we do not check
to see if the partition being powered up is valid/available. Fix this
by checking to see that the partition is valid/available.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/soc/tegra/pmc.c

@@ -549,6 +549,9 @@ int tegra_powergate_sequence_power_up(unsigned int id, struct clk *clk,
 	struct tegra_powergate pg;
 	int err;
 
+	if (!tegra_powergate_is_available(id))
+		return -EINVAL;
+
 	pg.id = id;
 	pg.clks = &clk;
 	pg.num_clks = 1;