media: nuvoton: Fix an error check in npcm_video_ece_init()

media: nuvoton: Fix an error check in npcm_video_ece_init()

When function of_find_device_by_node() fails, it returns NULL instead of
an error code. So the corresponding error check logic should be modified
to check whether the return value is NULL and set the error code to be
returned as -ENODEV.

Fixes: 46c15a4ff1f4 ("media: nuvoton: Add driver for NPCM video capture and encoding engine")
Cc: stable@vger.kernel.org
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20241015014053.669-1-thunder.leizhen@huawei.com
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>