mx7ulp: Allow to enable CONFIG_IMX_HAB

Secure boot support on mx7ulp was added in the
commit 27117b20 ("mx7ulp: Add HAB boot support").

Allow selecting CONFIG_IMX_HAB for ARCH_IMX7ULP.

Fixes: 27117b20 ("mx7ulp: Add HAB boot support")
Signed-off-by: Ricardo Salveti <ricardo@foundries.io>
Signed-off-by: Oleksandr Suvorov <oleksandr.suvorov@foundries.io>
Reviewed-by: Fabio Estevam <festevam@gmail.com>