ARM: imx: include iram.h rather than mach/iram.h

Rename mach-imx/include/mach/iram.h to mach-imx/iram.h, and update users
to include iram.h rather than mach/iram.h.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>