BACKPORT: of: property: fw_devlink: Add support for "leds" and "backlight"

Allows tracking dependencies between leds/backlights devices and their
consumers.

Link: https://lore.kernel.org/all/20210814023132.2729731-2-saravanak@google.com


Signed-off-by: Saravana Kannan <saravanak@google.com>
(cherry picked from commit 18c585c7)
Bug: 196400624
Signed-off-by: Ken Huang <kenbshuang@google.com>
Change-Id: I5efd7690f02c9fc375621d31558d82f343f5446f
Signed-off-by: Will McVicker <willmcvicker@google.com>