amdgpu: fix off by one in handle_table_insert

Stupid me, max_key must always be larger than key.

Signed-off-by: Christian König <christian.koenig@amd.com>
Bugzilla: https://bugs.freedesktop.org/107552


Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Junwei Zhang <Jerry.Zhang@amd.com>