armv8: layerscape: Enable falcon boot

Add jump_to_image_linux() for arm64. Add "noreturn" flag to
armv8_switch_to_el2(). Add hooks to fsl-layerscape to enable falcon
boot.

Signed-off-by: York Sun <york.sun@nxp.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Łukasz Majewski <lukma@denx.de>
Tested-by: Łukasz Majewski <lukma@denx.de>