board: apalis-imx8: add new 8gb product variant

Add the new Apalis iMX8 product variant

0067: Apalis iMX8 QuadMax 8GB Wi-Fi / BT IT

the only difference to the product

0037 Apalis iMX8 QuadMax 4GB Wi-Fi / BT IT

is the 8gb of RAM. Toradex strategy to choose the correct RAM timing in
SCFW is by fuses in the user area telling which RAM timing to load.

This commit makes use of this information to set the correct size of
the RAM and therefore distinguish between the new 0067 and 0037 product

Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
Reviewed-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Acked-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>