arm64: xilinx: Guard distro boot variable generation

When distro boot is disabled there is no reason to generate variables for
it. Also do not update boot_targets variable because it would be unused.

It is useful for example when standard boot is enabled and distro boot
is disabled.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/570c51435da59831ec245cddceda078afa58a550.1693913398.git.michal.simek@amd.com
diff --git a/board/xilinx/versal-net/board.c b/board/xilinx/versal-net/board.c
index 7ad299f..c18be0c 100644
--- a/board/xilinx/versal-net/board.c
+++ b/board/xilinx/versal-net/board.c
@@ -194,7 +194,7 @@
 	return bootmode;
 }
 
-int board_late_init(void)
+static int boot_targets_setup(void)
 {
 	u8 bootmode;
 	struct udevice *dev;
@@ -205,14 +205,6 @@
 	char *new_targets;
 	char *env_targets;
 
-	if (!(gd->flags & GD_FLG_ENV_DEFAULT)) {
-		debug("Saved variables - Skipping\n");
-		return 0;
-	}
-
-	if (!IS_ENABLED(CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG))
-		return 0;
-
 	bootmode = versal_net_get_bootmode();
 
 	puts("Bootmode: ");
@@ -320,6 +312,28 @@
 
 		env_set("boot_targets", new_targets);
 	}
+
+	return 0;
+}
+
+int board_late_init(void)
+{
+	int ret;
+
+	if (!(gd->flags & GD_FLG_ENV_DEFAULT)) {
+		debug("Saved variables - Skipping\n");
+		return 0;
+	}
+
+	if (!IS_ENABLED(CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG))
+		return 0;
+
+	if (IS_ENABLED(CONFIG_DISTRO_DEFAULTS)) {
+		ret = boot_targets_setup();
+		if (ret)
+			return ret;
+	}
+
 	return board_late_init_xilinx();
 }