feat(imx8mq): add BL31 PIE support

Enable PIE support so the BL31 firmware can be loaded from anywhere
within the OCRAM (SRAM). For the PIE support we only need to replace
the BL31_BASE define by the BL31_START symbol which is a relocatable
and we need to enable it by setting ENABLE_PIE := 1.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Change-Id: Ie6a13e4ae0fdc6627a94798d7a86df7d5b310896
diff --git a/plat/imx/imx8m/imx8mq/imx8mq_psci.c b/plat/imx/imx8m/imx8mq/imx8mq_psci.c
index 662017d..01582af 100644
--- a/plat/imx/imx8m/imx8mq/imx8mq_psci.c
+++ b/plat/imx/imx8m/imx8mq/imx8mq_psci.c
@@ -41,7 +41,7 @@
 
 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);