plat: imx8m: refactor the code to make it reusable

for the i.MX8M SOCs, part of the code for gpc
and PSCI implementation can be reused and make it
common for all these SoCs. this patch extracts
the common part for reuse.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>
diff --git a/plat/imx/imx8m/include/imx8m_psci.h b/plat/imx/imx8m/include/imx8m_psci.h
new file mode 100644
index 0000000..4966403
--- /dev/null
+++ b/plat/imx/imx8m/include/imx8m_psci.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2019, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef IMX8M_PSCI_H
+#define IMX8M_PSCI_H
+
+#define CORE_PWR_STATE(state) ((state)->pwr_domain_state[MPIDR_AFFLVL0])
+#define CLUSTER_PWR_STATE(state) ((state)->pwr_domain_state[MPIDR_AFFLVL1])
+#define SYSTEM_PWR_STATE(state) ((state)->pwr_domain_state[PLAT_MAX_PWR_LVL])
+
+int imx_pwr_domain_on(u_register_t mpidr);
+void imx_pwr_domain_on_finish(const psci_power_state_t *target_state);
+void imx_pwr_domain_off(const psci_power_state_t *target_state);
+int imx_validate_ns_entrypoint(uintptr_t ns_entrypoint);
+int imx_validate_power_state(unsigned int power_state, psci_power_state_t *rq_state);
+void imx_cpu_standby(plat_local_state_t cpu_state);
+void imx_domain_suspend(const psci_power_state_t *target_state);
+void imx_domain_suspend_finish(const psci_power_state_t *target_state);
+void imx_get_sys_suspend_power_state(psci_power_state_t *req_state);
+void __dead2 imx_system_reset(void);
+void __dead2 imx_system_off(void);
+void __dead2 imx_pwr_domain_pwr_down_wfi(const psci_power_state_t *target_state);
+
+#endif /* IMX8M_PSCI_H */