VideoFrameSchedulerBase: fix overflow in PLL::fit()

PLL::fit() may have addition or multiplication
overflow problem.

Bug: 129491498
Test: TBD

Change-Id: Id9b4bc0d2e53c1b4c239027c8b087020019a0147
(cherry picked from commit 3ba81e73eb15b809373da491dae4e7fe2792aa13)
1 file changed