leds: various: use only available OF children

leds: various: use only available OF children

Various drivers count and iterate over OF children nodes via
of_get_child_count and for_each_child_of_node. Instead they should use
of_get_available_child_count and for_each_available_child_of_node, so
that if a given node has the `status` property set to `disabled`, the
child will be ignored.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Andrey Utkin <andrey_utkin@fastmail.com>
Cc: Baolin Wang <baolin.wang7@gmail.com>
Cc: Baolin Wang <baolin.wang@linaro.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Christian Mauderer <oss@c-mauderer.de>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: Dan Murphy <dmurphy@ti.com>
Cc: David Rivshin <drivshin@allworx.com>
Cc: Haojian Zhuang <haojian.zhuang@marvell.com>
Cc: H. Nikolaus Schaller <hns@goldelico.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Milo Kim <milo.kim@ti.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Nikita Travkin <nikitos.tr@gmail.com>
Cc: Orson Zhai <orsonzhai@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Philippe Retornaz <philippe.retornaz@epfl.ch>
Cc: Riku Voipio <riku.voipio@iki.fi>
Cc: Simon Guinot <sguinot@lacie.com>
Cc: Simon Shields <simon@lineageos.org>
Cc: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Cc: Xiaotong Lu <xiaotong.lu@spreadtrum.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>