Allow displaying the U-Boot banner on a video display

At present the U-Boot banner is only displayed on the serial console. If
this is not visible to the user, the banner does not show. Some devices
have a video display which can usefully display this information.

Add a banner which is printed after relocation only on non-serial devices
if CONFIG_DISPLAY_BOARDINFO_LATE is defined.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Stephen Warren <swarren@nvidia.com>