video: clps711x-fb: release disp device node in probe()

clps711x_fb_probe() increments refcnt of disp device node by
of_parse_phandle() and leaves it undecremented on both
successful and error paths.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Cc: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>