imx: imx8qm/imx8qxp: Power down the resources before SPL jump to u-boot

Make sure that all devices that are powered up by SPL are powered down
before entering into the u-boot. Otherwise the subsystem/device will
never be powered down by SCFW, due to SPL and u-boot are in different
partitions.

Benefiting from power domain driver, this patch implements the function
"imx8_power_off_pd_devices" to power off all active devices.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/board/freescale/imx8qm_mek/spl.c b/board/freescale/imx8qm_mek/spl.c
index cb4006e..ba99002 100644
--- a/board/freescale/imx8qm_mek/spl.c
+++ b/board/freescale/imx8qm_mek/spl.c
@@ -12,6 +12,7 @@
 #include <dm/uclass-internal.h>
 #include <dm/device-internal.h>
 #include <dm/lists.h>
+#include <asm/arch/sys_proto.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -37,6 +38,11 @@
 	puts("Normal Boot\n");
 }
 
+void spl_board_prepare_for_boot(void)
+{
+	imx8_power_off_pd_devices(NULL, 0);
+}
+
 #ifdef CONFIG_SPL_LOAD_FIT
 int board_fit_config_name_match(const char *name)
 {