msm: mdss: Add HFP_CALC_CLK way to switch frame rate

Add support to switch non-standard framerate.To achieve this,
first map the fps to standard fps and then tune pixel clock
based non-standard framerate. Panel porches might need update
before pixel clock tuning based on standard framerate mapping.

CRs-fixed: 1032036
Change-Id: I49995875338cd2a3b57e88753cfda1bfa97910dd
Signed-off-by: feifanz <feifanz@codeaurora.org>
Signed-off-by: Krishna Srinivas <krisrini@codeaurora.org>