spl: Rename SYS_SPL_ARGS_ADDR to SPL_PAYLOAD_ARGS_ADDR

Rename this so that SPL is first, as per U-Boot convention. Also add
PAYLOAD_ since this is where in memory the parameters for the payload
have been stored.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/common/spl/spl_ext.c b/common/spl/spl_ext.c
index 2bf3434..902564a 100644
--- a/common/spl/spl_ext.c
+++ b/common/spl/spl_ext.c
@@ -97,7 +97,7 @@
 			puts("spl: ext4fs_open failed\n");
 			goto defaults;
 		}
-		err = ext4fs_read((void *)CONFIG_SYS_SPL_ARGS_ADDR, 0, filelen, &actlen);
+		err = ext4fs_read((void *)CONFIG_SPL_PAYLOAD_ARGS_ADDR, 0, filelen, &actlen);
 		if (err < 0) {
 			printf("spl: error reading image %s, err - %d, falling back to default\n",
 			       file, err);
@@ -127,7 +127,7 @@
 	if (err < 0)
 		puts("spl: ext4fs_open failed\n");
 
-	err = ext4fs_read((void *)CONFIG_SYS_SPL_ARGS_ADDR, 0, filelen, &actlen);
+	err = ext4fs_read((void *)CONFIG_SPL_PAYLOAD_ARGS_ADDR, 0, filelen, &actlen);
 	if (err < 0) {
 #ifdef CONFIG_SPL_LIBCOMMON_SUPPORT
 		printf("%s: error reading image %s, err - %d\n",