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_bl31_setup.c b/plat/imx/imx8m/imx8mq/imx8mq_bl31_setup.c
index 61c92a2..4706c20 100644
--- a/plat/imx/imx8m/imx8mq/imx8mq_bl31_setup.c
+++ b/plat/imx/imx8m/imx8mq/imx8mq_bl31_setup.c
@@ -176,7 +176,7 @@
 void bl31_plat_arch_setup(void)
 {
 	const mmap_region_t bl_regions[] = {
-		MAP_REGION_FLAT(BL31_BASE, BL31_SIZE,
+		MAP_REGION_FLAT(BL31_START, BL31_SIZE,
 				MT_MEMORY | MT_RW | MT_SECURE),
 		MAP_REGION_FLAT(BL_CODE_BASE, BL_CODE_END - BL_CODE_BASE,
 				MT_MEMORY | MT_RO | MT_SECURE),