clk: qcom: mdss: update PLL VCO frequency range to change clock phase

Change the VCO frequency range to avoid display fading issues.
Add code to change the PLL dividers to match the new
VCO frequency range.

Change-Id: Iec62f6be26d47cdfd8b2acb895f2e80d57164833
Signed-off-by: Chandan Uddaraju <chandanu@codeaurora.org>