ARM: tegra: clean-up mach/io.h

Move tegra specific mach/io.h parts into iomap.h.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Cc: Colin Cross <ccross@android.com>
Cc: Olof Johansson <olof@lixom.net>