Input: imx6ul_tsc - fix error handling

If imx6ul_tsc_init() fails we should not return directly.

We should disable the previously acquired clocks in this case.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>