ARM: dts: msm: enable 90 phase dsi vco frequency for msm8992

Enable DSI PLL VCO phase configuration to have 90 phase
difference between dsi bit clock and dsi byte clock.

Change-Id: If6882a5b61caed8f3b48a7329e1f15034f49602b
Signed-off-by: Chandan Uddaraju <chandanu@codeaurora.org>