ARM: imx27: Get rid of mm-imx27.c

Get rid of mm-imx27.c and move its code to the mach-imx27.c file.

This aligns with other i.MX SoC code.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>