iommu/amd: Add ioapic and hpet ivrs override

Add two new kernel commandline parameters ivrs_ioapic and
ivrs_hpet to override the Id->DeviceId mapping from the IVRS
ACPI table. This can be used to work around broken BIOSes to
get interrupt remapping working on AMD systems.

Tested-by: Borislav Petkov <bp@suse.de>
Tested-by: Suravee Suthikulanit <suravee.suthikulpanit@amd.com>
Reviewed-by: Shuah Khan <shuahkhan@gmail.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>