Don't load env partition from flash if secure boot

We cannot trust the contents of the NOR flash since it is not
cryptographically signed. A malicious script that is stored in the env
partition on the NOR flash could be used to compromise the security of
the system. Let's just ignore the env partition.

Change-Id: Id0510ced0f932e9bc15fb292f84e1fe863483a29
1 file changed