Tegra186: sanity check power state type

This patch sanity checks the power state type before use,
from the platform's PSCI handler.

Verified with TFTF Standard Test Suite.

Change-Id: Icd45faac6c023d4ce7f3597b698d01b91a218124
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>

plat/nvidia/tegra/soc/t186/plat_psci_handlers.c

@@ -72,6 +72,11 @@ int32_t tegra_soc_validate_power_state(uint32_t power_state,
 	case PSTATE_ID_CORE_IDLE:
 	case PSTATE_ID_CORE_POWERDN:
 
+		if (psci_get_pstate_type(power_state) != PSTATE_TYPE_POWERDOWN) {
+			ret = PSCI_E_INVALID_PARAMS;
+			break;
+		}
+
 		/* Core powerdown request */
 		req_state->pwr_domain_state[MPIDR_AFFLVL0] = state_id;
 		req_state->pwr_domain_state[MPIDR_AFFLVL1] = state_id;