mdss: display: implement common irq handler for different mdss blocks

All of MDSS blocks (mdp, dsi, edp, hdmi) share same irq line. Implement
function to manage MDSS irq line with common API with support for irq
callback handler for each of block. Also fix incorrect calculation of
MDP interface interrupts.

Change-Id: I1271f7e1065aac95175b6e92504917264f4043a5
Signed-off-by: Adrian Salido-Moreno <adrianm@codeaurora.org>