clk: qcom: HDMI source sel is 3 not 2

The HDMI PLL input to the tv mux is supposed to be 3, not 2. Fix
the code so that we can properly select the HDMI PLL.

Fixes: 6d00b56f

 "clk: qcom: Add support for MSM8960's multimedia clock controller (MMCC)"
Reported-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>