mtd: docg3 fix missing bitreverse lib

Fix missing dependency which can cause a build error such
as: ERROR: "byte_rev_table" [drivers/mtd/devices/docg3.ko]
undefined!

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/devices/Kconfig b/drivers/mtd/devices/Kconfig
index 27f80cd..46dcb54 100644
--- a/drivers/mtd/devices/Kconfig
+++ b/drivers/mtd/devices/Kconfig
@@ -272,6 +272,7 @@
 	tristate "M-Systems Disk-On-Chip G3"
 	select BCH
 	select BCH_CONST_PARAMS
+	select BITREVERSE
 	---help---
 	  This provides an MTD device driver for the M-Systems DiskOnChip
 	  G3 devices.