mtd: parsers: ofpart: support Linksys Northstar partitions

This allows extending ofpart parser with support for Linksys Northstar
devices. That support uses recently added quirks mechanism.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210312134919.7767-2-zajec5@gmail.com