nand : Add Freescale iMX27 nand flash controller support

This patch add support of iMX27 nand flash controller. This is based on
driver for imx31 nand flash controller.
OOB functionality is not fully working. As in mx31 controller, mx2 NFC
has a bug that swap two bytes between SPARE and MAIN buffer.
I used this driver for several months and no problems appear.

src/flash/nand/Makefile.am

@@ -18,6 +18,7 @@ NAND_DRIVERS = \
 	nonce.c \
 	davinci.c \
 	lpc3180.c \
+	mx2.c \
 	mx3.c \
 	orion.c \
 	s3c24xx.c \
@@ -35,6 +36,7 @@ noinst_HEADERS = \
 	fileio.h \
 	imp.h \
 	lpc3180.h \
+	mx2.h \
 	mx3.h \
 	s3c24xx.h \
 	s3c24xx_regs.h