iommu: Rename intr_remapping files to intel_intr_remapping

The files contain code mostly relevant for the Intel
implementation of interrupt remapping. Make that visible in
the file names. Also inline intr_remapping.h into
intr_remapping.c because it is only included there and the
content is very small. So there is no reason for a seperate
header file.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>