mtd: Drop duplicate MTD_PARTITIONS Kconfig option

Commit 9c5b00973bce ("Convert CONFIG_MTD_PARTITIONS et al to Kconfig")
introduced a publicly visible Kconfig entry for the
CONFIG_MTD_PARTITIONS option, while the rework on MTD partitioning
was in progress, and we somehow did not notice that the same Kconfig
entry was added by commit 4048a5c519a8 ("mtd: declare MTD_PARTITIONS
symbol in Kconfig"), but this time as an invisible entry (this can
only be selected by other options).

Keep the non-visible version of this symbol, since MTD_PARTITIONS is
not something the user should be able to enable/disable directly.

Fixes: 4048a5c519a8 ("mtd: declare MTD_PARTITIONS symbol in Kconfig")
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/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
index 11cf12b..0050fb2 100644
--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -22,12 +22,6 @@
 	  Adds the MTD device infrastructure from the Linux kernel.
 	  Needed for mtdparts command support.
 
-config MTD_PARTITIONS
-	bool "Add MTD Partioning infrastructure"
-	help
-	  Adds the MTD partitioning infrastructure from the Linux
-	  kernel. Needed for UBI support.
-
 config FLASH_CFI_DRIVER
 	bool "Enable CFI Flash driver"
 	help