configs: Add configs for J721e High Security EVM

Add new defconfig files for the J721e High Security EVM.

These defconfigs are the same as for the non-secure part, except for:
    CONFIG_TI_SECURE_DEVICE option set to 'y'
    CONFIG_FIT_IMAGE_POST_PROCESS option set to 'y'
    CONFIG_SPL_FIT_IMAGE_POST_PROCESS option set to 'y'
    CONFIG_BOOTCOMMAND uses FIT images for booting

Signed-off-by: Andrew F. Davis <afd@ti.com>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>