uboot-imx

tegra: Boot in non-secure mode by default

Upstream Linux is broken with default configs when PSCI, thus non-secure
mode is enabled. So the user should explicitly enable this mode, e.g.
when she disabled CONFIG_CPU_IDLE in Linux (in which case it's safe to
use). We can revert this workaround once Linux got fixed.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>