feat(imx8m): make psci common code pie compatible

Swap the BL31_BASE define with the BL31_START symbol. This is required
for later added PIE support because the symbol location can be relocated
whereas the define can't be relocated. In case of disabled PIE support
BL31_START equals BL31_BASE and so we don't need a ifdef.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Change-Id: Ic1bbf3af5b346898bfcbb207ffc27d9a5bdcaae7
diff --git a/plat/imx/imx8m/imx8m_psci_common.c b/plat/imx/imx8m/imx8m_psci_common.c
index 4df4f8e..aab8497 100644
--- a/plat/imx/imx8m/imx8m_psci_common.c
+++ b/plat/imx/imx8m/imx8m_psci_common.c
@@ -40,7 +40,7 @@
 int imx_pwr_domain_on(u_register_t mpidr)
 	unsigned int core_id;
-	uint64_t base_addr = BL31_BASE;
+	uint64_t base_addr = BL31_START;
 	core_id = MPIDR_AFFLVL0_VAL(mpidr);
@@ -102,7 +102,7 @@
 void imx_domain_suspend(const psci_power_state_t *target_state)
-	uint64_t base_addr = BL31_BASE;
+	uint64_t base_addr = BL31_START;
 	uint64_t mpidr = read_mpidr_el1();
 	unsigned int core_id = MPIDR_AFFLVL0_VAL(mpidr);