ARM: imx: move debug macros to include/debug

Move imx debug-macro.S over to common debug macro directory.  It
removes the inclusion to hardware.h by hard-coding the physical
address of uart port and copying IMX_IO_P2V from hardware.h.

Since we will need a common solution, which might use a fixed virtual
address for uart port across platforms, we make a copy of IMX_IO_P2V
here as a temporary solution to enable low-level debug for imx
multi-platform build.

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