arm64: dts: qcom: sm8650: Fix domain-idle-state for CPU2

arm64: dts: qcom: sm8650: Fix domain-idle-state for CPU2

On SM8650 the CPUs 0-1 are "silver" (Cortex-A520), CPU 2-6 are "gold"
(Cortex-A720) and CPU 7 is "gold-plus" (Cortex-X4).

So reference the correct "gold" idle-state for CPU core 2.

Fixes: d2350377997f ("arm64: dts: qcom: add initial SM8650 dtsi")
Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250314-sm8650-cpu2-sleep-v1-1-31d5c7c87a5d@fairphone.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>