layerscape: armv8_64b: enable CONFIG_ARM_PSCI_CPUIDLE

Enable PSCI firmware based CPUidle driver.
PSCI firmware is the standard power management control for all ARM64
based platforms.

Signed-off-by: Martin Schiller <[email protected]>

target/linux/layerscape/armv8_64b/config-5.4

@@ -56,6 +56,7 @@ CONFIG_ARM_GIC_V3_ITS=y
 CONFIG_ARM_GIC_V3_ITS_FSL_MC=y
 CONFIG_ARM_GIC_V3_ITS_PCI=y
 # CONFIG_ARM_PL172_MPMC is not set
+CONFIG_ARM_PSCI_CPUIDLE=y
 CONFIG_ARM_PSCI_FW=y
 CONFIG_ARM_SMMU=y
 # CONFIG_ARM_SMMU_DISABLE_BYPASS_BY_DEFAULT is not set