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/at91sam9261ek_nandflash_defconfig b/configs/at91sam9261ek_nandflash_defconfig
index 0891204..d69d400 100644
--- a/configs/at91sam9261ek_nandflash_defconfig
+++ b/configs/at91sam9261ek_nandflash_defconfig
@@ -38,7 +38,7 @@
 CONFIG_DM_GPIO=y
 CONFIG_AT91_GPIO=y
 # CONFIG_MMC is not set
-CONFIG_NAND=y
+CONFIG_MTD_RAW_NAND=y
 # CONFIG_SYS_NAND_USE_FLASH_BBT is not set
 CONFIG_NAND_ATMEL=y
 CONFIG_DM_SPI_FLASH=y