do_div() macro to perform u64 division and guards against overflow if
the result is too large for the unsigned long return type.
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Link: https://lkml.kernel.org/r/20200114160726.19771-1-dinguyen@kernel.orgSigned-off-by: Stephen Boyd <sboyd@kernel.org>