iommu: Change trace unmap api to report unmapped size

Currently map and unmap are implemented as events under a
common trace class declaration. The common class forces
trace_unmap() to require a bogus physical address argument
that it doesn't use. Changing unmap to report unmapped size
will provide useful information for debugging. Remove common
map_unmap trace class and change map and unmap into separate
events as opposed to events under the same class to allow for
differences in the reporting information. In addition, map and
unmap are changed to handle size value as size_t instead of int
to match the passed size value and avoid overflow.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>