SPL: make jump_to_image_no_args a weak symbol

Change jump_to_image_no_args() to a weak symbol to allow override by
SoC specific code.  This is required by tegra because the SPL runs on
a different CPU from the image it is loading, so tegra specific
initialization is required to start the host CPU.  Pass in spl_image
as a parameter for the same reason.

Signed-off-by: Allen Martin <amartin@nvidia.com>
Acked-by: Tom Rini <trini@ti.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>