ARM: dts: omap: align LED node names with dtschema

The node names should be generic and DT schema expects certain pattern:

  omap3-beagle-ab4.dtb: leds: 'heartbeat', 'mmc', 'pmu_stat' do not match any of the regexes: '(^led-[0-9a-f]$|led)', 'pinctrl-[0-9]+'

Acked-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20221127203034.54092-1-krzysztof.kozlowski@linaro.org


Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>