serial: tegra: Add missing clk_disable_unprepare() in tegra_uart_hw_init()

Add the missing clk_disable_unprepare() before return from
tegra_uart_hw_init() in the error handling path.
When request_irq() fails in tegra_uart_startup(), 'tup->uart_clk'
has been enabled, fix it by adding clk_disable_unprepare().

Fixes: cc9ca4d9 ("serial: tegra: Only print FIFO error message when an error occurs")
Fixes: d781ec21

 ("serial: tegra: report clk rate errors")
Signed-off-by: Yi Yang <yiyang13@huawei.com>
Link: https://lore.kernel.org/r/20221126020852.113378-1-yiyang13@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>