drm/amdgpu: remove redundant variable r and redundant return statement
There is a return statement that is not reachable and a variable that
is not used. Remove them.
Addresses-Coverity: ("Structurally dead code") Fixes: de7b45babd9b ("drm/amdgpu: cleanup creating BOs at fixed location (v2)") Reviewed-by: Christian König <christian.koenig@amd.com> Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>