ARM: tegra: move iomap.h to mach-tegra

Nothing outside mach-tegra uses this file, so there's no need for it to
be in <mach/>.

Since uncompress.h and debug-macro.S remain in include/mach, they need
to include "../../iomap.h" becaue of this change. uncompress.h will soon
be deleted in later multi-platform/single-zImage patches. debug-macro.S
will need to continue to include this header using an explicit relative
path, to avoid duplicating the physical->virtual address mapping that
iomap.h dictates.

Signed-off-by: Stephen Warren <swarren@nvidia.com>