intel-iommu: change the copyright information.

Change the copyright information of intel_iommu.c and intel_iommu.h to
standard form used in QEMU.

Signed-off-by: Le Tan <tamlokveer@gmail.com>
intel-iommu: change D() to VTD_DPRINTF() and delete some dead code

Chang D() to VTD_DPRINTF() to avoid polluting the global namespace.
Delete some dead code which has been commented out before.

Signed-off-by: Le Tan <tamlokveer@gmail.com>
intel-iommu: rename some CSRs access functions

Rename some CSRs access funcionts:
__get_quad() -> get_quad_raw()
__get_long() -> get_long_raw()
set_mask_quad() -> set_claer_mask_quad()
set_mask_long() -> set_clear_mask_long()

Signed-off-by: Le Tan <tamlokveer@gmail.com>
intel-iommu: use assert() to check the return value of dma_memory_read()

Use assert() to check dma_memory_read() rather than print some warning and
return invalid value, since we can do nothing more than aobrt if
dma_memory_read() fail.

Signed-off-by: Le Tan <tamlokveer@gmail.com>
intel-iommu: rename constant definitions with consistent prefix

Rename some constant definitions with consistent prefix VTD_.
Remove unused constant definitions.

Signed-off-by: Le Tan <tamlokveer@gmail.com>
intel-iommu: rename struct vtd_root_entry and vtd_context_entry

Rename two struct:
vtd_root_entry -> VTDRootEntry
vtd_context_entry -> VTDContextEntry

Signed-off-by: Le Tan <tamlokveer@gmail.com>