msm: mdss: Remove additional clk refcnts in dual-dsi

When dual-dsi panel is attached to a device, both DSI controllers
are registered to mdss. But only one registration done notification
needs to be sent. Currently two notifications are sent and it leads
to an additional refcnt on mdp clocks which in turn prevents proper
suspend. Fix this by sending notification only once.

Change-Id: I29e3c92e9ab0cccd9314cc5428b4accc31b0d0d9
Signed-off-by: Ujwal Patel <ujwalp@codeaurora.org>
msm: mdss: Notify userspace of idle screen case

Expose two new sysfs nodes - idle_time and idle_notify - that
are used to notify userspace whenever the display is idle with
no screen updates. The idle_time node needs to be configured
with the duration in milliseconds to detect no screen updates.
The userspace app can poll on the idle_notify node to get
notifications of the idle state.

Change-Id: I7435a084ad2c928d952c5d106ff9ef92aaa385b9
Signed-off-by: Aravind Venkateswaran <aravindh@codeaurora.org>