mtd: mtdoops: kill Kconfig usage instructions

The mtdoops usage instructions found in Kconfig have been incorrect
since:

    commit 2e386e4b
    mtd: mtdoops: refactor as a kmsg_dumper

mtdoops no longer uses a console. Now, if you build it into your kernel,
you add something like the following to your command line to select
partition X as your logging partition:

    mtdoops.mtddev=X

Anyway, it seems better to leave the documentation out of Kconfig.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/Kconfig

@@ -304,9 +304,6 @@ config MTD_OOPS
 	  buffer in a flash partition where it can be read back at some
 	  later point.
 
-	  To use, add console=ttyMTDx to the kernel command line,
-	  where x is the MTD device number to use.
-
 config MTD_SWAP
 	tristate "Swap on MTD device support"
 	depends on MTD && SWAP