[U-Boot] [PATCH 02/21] sandbox: Check the filename in jump_to_image_no_args()

[sjg at google.com]

If the filename is NULL this function currently crashes. Update it to fail
gracefully.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

 arch/sandbox/cpu/spl.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

Applied to u-boot-dm/master, thanks!