x86: coral: Put the eMMC first

At present the eMMC device does not have an alias so it appears after
the SD card which is device 1. There is no device 0 which is odd.

Make the eMMC device be the first one. Update the boot script to use the
new device.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
2 files changed