Add support for Eukrea's CPUIMX27

CPUIMX27 is built around Freescale's i.MX27 and has up to 64MB of
 NOR Flash, up to 512MB of NAND Flash and up to 256MB of mDDR,
 it includes an ethernet PHY in MII mode, an I2C RTC and a
 ST16554 QuadUART on nCS3.

Signed-off-by: Eric Benard <eric@eukrea.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>