cmd: pxe_utils: Check fdtcontroladdr in label_boot

If using OF_CONTROL, fdtcontroladdr is set to the fdt used to configure
U-Boot. When using PXE, if no fdt is defined in the menu file, and
there is no fdt at fdt_addr, add fall back on fdtcontroladdr too.

We are developing board support for the Armv8r64 FVP using
config_distro_bootcmd. We are also using OF_BOARD and would like the
PXE boot option to default to the fdt provided by board_fdt_blob_setup.

Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Ramon Fried <rfried.dev@gmail.com>
diff --git a/boot/pxe_utils.c b/boot/pxe_utils.c
index a7a84f2..a32acca 100644
--- a/boot/pxe_utils.c
+++ b/boot/pxe_utils.c
@@ -550,7 +550,10 @@
 	 * Scenario 2: If there is an fdt_addr specified, pass it along to
 	 * bootm, and adjust argc appropriately.
 	 *
-	 * Scenario 3: fdt blob is not available.
+	 * Scenario 3: If there is an fdtcontroladdr specified, pass it along to
+	 * bootm, and adjust argc appropriately.
+	 *
+	 * Scenario 4: fdt blob is not available.
 	 */
 	bootm_argv[3] = env_get("fdt_addr_r");
 
@@ -652,6 +655,9 @@
 	if (!bootm_argv[3])
 		bootm_argv[3] = env_get("fdt_addr");
 
+	if (!bootm_argv[3])
+		bootm_argv[3] = env_get("fdtcontroladdr");
+
 	if (bootm_argv[3]) {
 		if (!bootm_argv[2])
 			bootm_argv[2] = "-";