media: mtk-vcodec: add missing put_device() call in mtk_vcodec_release_dec_pm()

mtk_vcodec_release_dec_pm() will be called in two places:

a. mtk_vcodec_init_dec_pm() succeed while mtk_vcodec_probe() return error.
b. mtk_vcodec_dec_remove().

In both cases put_device() call is needed, since of_find_device_by_node()
was called in mtk_vcodec_init_dec_pm() previously.

Thus add put_devices() call in mtk_vcodec_release_dec_pm()

Fixes: 590577a4 ("[media] vcodec: mediatek: Add Mediatek V4L2 Video Decoder Driver")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>