ARM: dts: exynos: Fix schema warnings for pwm-leds

ARM: dts: exynos: Fix schema warnings for pwm-leds

The node names for devices using the pwm-leds driver follow a certain
naming scheme (now).  Parent node name is not enforced, but recommended
by DT project.

  arch/arm/boot/dts/exynos5410-odroidxu.dt.yaml: pwmleds:
    'blueled', 'greenled' do not match any of the regexes: '^led(-[0-9a-f]+)?$', 'pinctrl-[0-9]+'
  arch/arm/boot/dts/exynos5422-odroidhc1.dt.yaml: pwmleds:
    'blueled' does not match any of the regexes: '^led(-[0-9a-f]+)?$', 'pinctrl-[0-9]+'
  From schema: Documentation/devicetree/bindings/leds/leds-pwm.yaml

Signed-off-by: Alexander Dahl <post@lespocky.de>
Link: https://lore.kernel.org/r/20201005203451.9985-8-post@lespocky.de
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>