x86: Don't try to boot Linux from SPL

Booting into linux from 64-bit U-Boot is not yet supported. Avoid bringing
in the bootm code until it is implemented.

Of course 32-bit U-Boot still supports booting into both 32- and 64-bit
kernels.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
1 file changed