[SPLASH] select current bootdevice for image location

board/seco/common/splash_source.c

 #include <common.h>
 #include <splash.h>
+#include <mmc.h>
 
 static struct splash_location splash_locations[] = {
 	{
@@ -12,6 +13,12 @@ static struct splash_location splash_locations[] = {
 
 int splash_screen_prepare(void)
 {
+	char devpart[16] = {0};
+	int dev_no = (int)mmc_get_env_dev();
+
+	snprintf(devpart, ARRAY_SIZE(devpart), "%d:1", dev_no);
+	splash_locations[0].devpart = devpart;
+
 	return splash_source_load(splash_locations,
 			  ARRAY_SIZE(splash_locations));
 }
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