mtd: Make {MTDIDS, MTDPARTS}_DEFAULT visible when MTD_PARTITIONS is selected

gwventana configs are relying on CMD_UBI to select CMD_MTDPARTS,
which is then making {MTDIDS,MTDPARTS}_DEFAULT options available.

We are about to remove the 'select CMD_MTDPARTS' statement in the
CMD_UBI entry, but if we do that without first making sure
{MTDIDS,MTDPARTS}_DEFAULT are visible, we end up with a build
failure when building gwventana configs.

Address that by adding a depends on MTD_PARTITIONS to
{MTDIDS,MTDPARTS}_DEFAULT which does the trick since CMD_UBI selects
MTD_UBI which in turn selects MTD_PARTITIONS.

We also get rid of the depends on CMD_MTD, since CMD_MTD also selects
MTD_PARTITIONS.

Reported-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Jagan Teki <jagan@openedev.com>
diff --git a/cmd/Kconfig b/cmd/Kconfig
index d66f710..9310a8b 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -1728,14 +1728,14 @@
 
 config MTDIDS_DEFAULT
 	string "Default MTD IDs"
-	depends on CMD_MTD || CMD_MTDPARTS || CMD_NAND || CMD_FLASH
+	depends on MTD_PARTITIONS || CMD_MTDPARTS || CMD_NAND || CMD_FLASH
 	help
 	  Defines a default MTD IDs list for use with MTD partitions in the
 	  Linux MTD command line partitions format.
 
 config MTDPARTS_DEFAULT
 	string "Default MTD partition scheme"
-	depends on CMD_MTD || CMD_MTDPARTS || CMD_NAND || CMD_FLASH
+	depends on MTD_PARTITIONS || CMD_MTDPARTS || CMD_NAND || CMD_FLASH
 	help
 	  Defines a default MTD partitioning scheme in the Linux MTD command
 	  line partitions format