board: presidio: Add Parallel NAND support

Set environment for Nand flash (U-boot 2020.04):
- add nand flash in the device tree
- add new default configuration file for G3 using parallel Nand
- set nand parameters in presidio_asic.h

Signed-off-by: Kate Liu <kate.liu@cortina-access.com>
Signed-off-by: Alex Nemirovsky <alex.nemirovsky@cortina-access.com>
CC: Tom Rini <trini@konsulko.com>
Reviewed-by: Tom Rini <trini@konsulko.com>