[SF] Update DisplayMode::Fps with PeakFps

Update to incorporate display refresh rate on
DisplayMode

With the addition of VRR, vsync period
does not necessarily represent the
refresh rate of the display, having a
peakRefreshRate that represents the
display peak refresh rate helps with
separating the concern of vsync period
being different from the peak refresh rate
supported by the device.

Test: atest libsurfaceflinger_unittest
BUG: 286048920
BUG: 284845445
Change-Id: I9d90e4def4cf3efcd5a696a4ec43fbf7698abfe4