iommu/amd: Remove redundant devid checks

Checking the return value of get_device_id() in a code-path which has
already done check_device() is not needed, as check_device() does the
same check and bails out if it fails.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Link: https://lore.kernel.org/r/20200527115313.7426-11-joro@8bytes.org