[MTD] OneNAND: Enhanced support for DDP (Dual Densitiy Packages)

Add density mask for better support of DDP chips.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/linux/mtd/onenand.h b/include/linux/mtd/onenand.h
index afaa634..d27fd12 100644
--- a/include/linux/mtd/onenand.h
+++ b/include/linux/mtd/onenand.h
@@ -84,6 +84,7 @@
 	void __iomem		*base;
 	unsigned int		chipsize;
 	unsigned int		device_id;
+	unsigned int		density_mask;
 	unsigned int		options;
 
 	unsigned int		erase_shift;