clk: atlas7: fix integer overflow in dto rate calculation
clk: atlas7: fix integer overflow in dto rate calculation

I cannot believe that I spend quite a lot time in finding this bug.
It seems a pitfall people tend to fall in.

In "int64 = int32 * int32", conversion from 32-bits to 64-bits comes
after the multiplication. So this statement may not work as expected.

Signed-off-by: Yibo Cai <e732a3f0de35687e82bda0008a72e443d2f69704@csr.com>
Signed-off-by: Barry Song <a856445693a373abed3e477bd705f7011cbd8a1d@csr.com>
Signed-off-by: Stephen Boyd <010521127f513270fe503d86ab8316ac5147f4b7@codeaurora.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs