msm_fb: hdmi: Soft debouncing logic improvements

Currently, HPD(Hot Plug Detection, a module used for detecting
HDMI cable connection) soft debouncing logic implements around
1 sec mechanism to stabilize HPD event detection. In case of
fast HPD connect/disconnect, it is missing a real HPD event.
This change implements a new debouncing logic in driver which
will make sure the first real HPD event is correctly processed
and at the end of debouncing processing, if there is a change
in HPD state, the changed state is also processed. This way we
always process the change of HPD states.

CRs-Fixed: 384513
Change-Id: I02d9814e4a55b7eec11a8e0d134c9ed9b5747422
Signed-off-by: Ajay Singh Parmar <aparmar@codeaurora.org>
Signed-off-by: Aravind Venkateswaran <aravindh@codeaurora.org>