rtc: ftrtc010: Fix error handling in ftrtc010_rtc_probe

In the error handling path, the clk_prepare_enable() function
call should be balanced by a corresponding 'clk_disable_unprepare()'
call , as already done in the remove function.

clk_disable_unprepare calls clk_disable() and clk_unprepare().
They will use IS_ERR_OR_NULL to check the argument.

Fixes: ac05fba3

 ("rtc: gemini: Add optional clock handling")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220403054912.31739-1-linmq006@gmail.com