drm/msm: correct dependency of COMMON_CLK

COMMON_CLK API 'devm_clk_register' is called inside
config DRM_MSM_HDMI, not in config DRM_MSM. Correct
the dependency on COMMON_CLK in config DRM_MSM_HDMI.

Change-Id: Ic2b41aad01824e2d8a0d20ffeacf74f826a94933
Signed-off-by: Maria Yu <aiquny@codeaurora.org>