This is just future proofing code, not something that can be triggered
in real life.  We're testing to make sure we don't shift wrap when we
do "1ull << i" so "i" has to be in the 0-63 range.  If it's 64 then we
have gone too far.
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>