drivers/rtc/rtc-88pm860x.c: add missing of_node_put()

Add missing of_node_put() to decrement the reference count.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Cc: Haojian Zhuang <haojian.zhuang@linaro.org>
Cc: Sachin Kamat <sachin.kamat@linaro.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>