The device is equipped with a GPS module, reporting data via /dev/ttyS1.
A TF card reader is also present. Only one of those components can be
used at once, since they share some PINs.
This commit adds two devicetree overlays to allow for the user to select
the desired configuration. Another overlay configuration to allow booting
from SD card is provided.
Signed-off-by: Enrico Mioso <mrkiko.rs@gmail.com>
