spl: Convert NVMe to spl_load

This converts the blk load method (used exclusively by NVMe) to use
spl_load. As a consequence, it also adds support for LOAD_FIT_FULL and
IMX images.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
3 files changed