soc/tegra: Fix an error handling path in tegra_powergate_power_up()
If an error occurs after a successful tegra_powergate_enable_clocks()
call, it must be undone by a tegra_powergate_disable_clocks() call, as
already done in the below and above error handling paths of this function.
Update the 'goto' to branch at the correct place of the error handling
path.