msm_fb: display: fix frame rate wrong calculation

For cmd mode the frame rate calculation result is wrong. Also in mdp
driver there are several places to do the same calculation. So fix the
wrong calculation and use a single func to do calculation.

Change-Id: Iab498fb446a1d9b8295d710ffa82618d2ab6fc07
Signed-off-by: Huaibin Yang <huaibiny@codeaurora.org>
3 files changed