winsys/radeon: Only add bo to hash table when creating flink

winsys/radeon: Only add bo to hash table when creating flink

The problem is that we mix bo handles and flinked names in the hash
table. Because kms type handles are not flinked they should not be
added to the hash table. If we do that we will sooner or later
get a situation where we will overwrite a correct entry because
the bo handle was the same as a flinked name.

Note: this is a candidate for the stable branches.

Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>