mtd: make ofpart buildable as a separate module

As ofpart now uses a standard mtd partitions parser interface, make it
buildable as a separate module. Also provide MODULE_DESCRIPTION and
MODULE_AUTHOR for this module.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Artem Bityutskiy <dedekind1@gmail.com>
diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
index 4be8373..cc02e21 100644
--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -137,7 +137,8 @@
 	  'physmap' map driver (CONFIG_MTD_PHYSMAP) does this, for example.
 
 config MTD_OF_PARTS
-	def_bool y
+	tristate "OpenFirmware partitioning information support"
+	default Y
 	depends on OF
 	help
 	  This provides a partition parsing function which derives