msm: Display: Fix the reference count for MDP and DSI clocks

The clk_enable() call for MDP and DSI clocks are called more
than necessary. These clocks were not turning off during
suspend mode for "continuous Splash screen feature" and
dtv. Fix this by calling clk_disable() functions whereever
needed.

Change-Id: I05469ad08497bead6171478413623da15fe49182
Signed-off-by: Chandan Uddaraju <chandanu@codeaurora.org>