backlight: sky81452-backlight: Remove unnecessary call to of_node_get()

`dev->of_node` already has a reference to the device_node and calling
of_node_get on it is unnecessary. All conresponding calls to
of_node_put are also removed.

Signed-off-by: Shresth Prasad <shresthprasad7@gmail.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20240502172121.8695-2-shresthprasad7@gmail.com


Signed-off-by: Lee Jones <lee@kernel.org>