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>
diff --git a/MAINTAINERS b/MAINTAINERS
index f9a26cc..a7a62df 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -200,6 +200,7 @@
 F:	drivers/i2c/i2c-cortina.h
 F:	drivers/mtd/nand/raw/cortina_nand.c
 F:	drivers/mtd/nand/raw/cortina_nand.h
+F:	configs/cortina_presidio-asic-pnand_defconfig
 
 ARM/CZ.NIC TURRIS MOX SUPPORT
 M:	Marek Behun <marek.behun@nic.cz>