clk: qcom: mdss: use correct HDMI PLL divider

HDMI PLL divider divsel_six is preferred over divsel_four
to keep vco range within goal limits to maintain margin.
To achieve this, its precedence order is toggled at mux
level. So reverse toggle the mux_sel value during mux
selection.

Change-Id: I90d98e061978109d65136bbd77641d6cfff9f61a
Signed-off-by: Narender Ankam <nankam@codeaurora.org>