imx: hab: Increase CSF_SIZE for i.MX6 and i.MX7 devices

imx: hab: Increase CSF_SIZE for i.MX6 and i.MX7 devices

In certain i.MX devices the encrypted boot image is failing to boot.

According to AN12056 "Encrypted Boot on HABv4 and CAAM Enabled Devices"
it's necessary to pad CSF to 0x2000 and append DEK blob.

In this case the total image size in boot data structure must cover the
entire binary otherwise the dek_blob won't be copied to memory and image
won't be decrypted.

Increase CSF_SIZE to 0x4000 to avoid such issue when booting encrypted
boot images.

Signed-off-by: Breno Lima <breno.lima@nxp.com>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Fabio Estevam <festevam@gmail.com>