arm: mx6: cm-fx6: add splash locations to cm-fx6

Add the following splash locations to cm-fx6:
* filesystem formatted mmc
* filesystem formatted usb
* filesystem formatted sata

Cc: Igor Grinberg <grinberg@compulab.co.il>
Cc: Tom Rini <trini@konsulko.com>
Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
Acked-by: Igor Grinberg <grinberg@compulab.co.il>