GPIO LEDs is not a bus, so drop unit-address and also start suffix
numbering from 0:

  Warning (unit_address_vs_reg): /soc/leds/led@7: node has a unit name, but no reg or ranges property
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230420075053.41976-6-krzysztof.kozlowski@linaro.org