7327218681
u-boot was crashing in qemu as the modeled hardware enforced overly
strict memory reads.
While this code will work on existing hardware, fix to avoid future issues.
Fixes: 12770d0df0 ("ast2600: spl: Add boot mode detection")
Link: https://gitlab.com/qemu-project/qemu/-/issues/2636
Signed-off-by: Joel Stanley <joel@jms.id.au>