backlight: lm3509_bl: Fix early returns in for_each_child_of_node()

backlight: lm3509_bl: Fix early returns in for_each_child_of_node()

The for_each_child_of_node() macro automatically decrements the child
refcount at the end of every iteration. On early exits, of_node_put()
must be used to manually decrement the refcount and avoid memory leaks.

The scoped version of the macro accounts for such early breaks, fixing
the early exits without the need for explicit calls to of_node_put().

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Julia Lawall <julia.lawall@inria.fr>
Closes: https://lore.kernel.org/r/202406172314.2vVgelaS-lkp@intel.com/
Fixes: b72755f5b577 ("backlight: Add new lm3509 backlight driver")
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://lore.kernel.org/r/20240624-lm3509_bl_scoped-v1-1-ceba9df38f23@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>