[MTD] [NAND] rtc_from4.c: use lib/bitrev.c

This patch converts drivers/mtd/nand/rtc_from4.c to use the new
lib/bitrev.c

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index b4b1656..c600868 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -90,6 +90,7 @@
 	depends on MTD_NAND && SH_SOLUTION_ENGINE
 	select REED_SOLOMON
 	select REED_SOLOMON_DEC8
+	select BITREVERSE
 	help
 	  This enables the driver for the Renesas Technology AG-AND
 	  flash interface board (FROM_BOARD4)