mtd: nand: Add core infrastructure to support SPI NANDs

Add a SPI NAND framework based on the generic NAND framework and the
spi-mem infrastructure.

In its current state, this framework supports the following features:

- single/dual/quad IO modes
- on-die ECC

Signed-off-by: Peter Pan <peterpandong@micron.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Jagan Teki <jagan@openedev.com>
diff --git a/drivers/mtd/nand/spi/Kconfig b/drivers/mtd/nand/spi/Kconfig
new file mode 100644
index 0000000..2197cb5
--- /dev/null
+++ b/drivers/mtd/nand/spi/Kconfig
@@ -0,0 +1,7 @@
+menuconfig MTD_SPI_NAND
+	bool "SPI NAND device Support"
+	depends on MTD && DM_SPI
+	select MTD_NAND_CORE
+	select SPI_MEM
+	help
+	  This is the framework for the SPI NAND device drivers.