Regarding your query I am afraid to say, we have not tested display over SPI. The supported interface for Colibri family are 18 bit parallel RGB(with vysnc, plk, hsync, polarity), HDMI(if module support), LVDS from RGB. If possible I will suggest you to find 5 inch display on parallel interface which will be more easy to interface. Please check Colibri iMX7 datasheet for more info on same.
If you really need to interface same display, you are required to build custom kernel with driver for the same. There is driver available but we never tested same.
Please check below link for reference