mtd: ensure MTD/the raw NAND core are compiled when there is a NAND flash

Both symbols must be enabled when there is a raw NAND driver
selected. Also enable them when CONFIG_CMD_NAND is selected to avoid
breaking things when we'll further rework the MTD dependency
description.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
[trini: Rebase and migrate a few more boards here]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/db-mv784mp-gp_defconfig b/configs/db-mv784mp-gp_defconfig
index 47fb304..879703d 100644
--- a/configs/db-mv784mp-gp_defconfig
+++ b/configs/db-mv784mp-gp_defconfig
@@ -73,3 +73,4 @@
 CONFIG_DM_USB=y
 CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_STORAGE=y
+CONFIG_MTD=y