ARM: dts: msm: enable dynamic fps vfp mode for sharp wqxga panel

The display frame rate can be dynamically changed by changing vertical
front porch values for this panel. Enable this feature and specify the
minimum and maximum refresh rate supported by this panel.

Change-Id: Ifee2353398f6594bd174aa403e0c8eafe1d3028c
Signed-off-by: Huaibin Yang <huaibiny@codeaurora.org>