mtd: rename CONFIG_NAND -> CONFIG_MTD_RAW_NAND

Add more clarity by changing the Kconfig entry name.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
[trini: Re-run migration, update a few more cases]
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
diff --git a/configs/bcm968580xref_ram_defconfig b/configs/bcm968580xref_ram_defconfig
index 001e8d8..9e86084 100644
--- a/configs/bcm968580xref_ram_defconfig
+++ b/configs/bcm968580xref_ram_defconfig
@@ -33,7 +33,7 @@
 CONFIG_LED_BLINK=y
 # CONFIG_MMC is not set
 CONFIG_MTD=y
-CONFIG_NAND=y
+CONFIG_MTD_RAW_NAND=y
 CONFIG_NAND_BRCMNAND=y
 CONFIG_NAND_BRCMNAND_6858=y
 CONFIG_DM_SPI_FLASH=y