drm/msm/sde: add multi-client and ref counting for core irq

Add multiple client support for core irq interface. Multiple
clients can register/unregister callbacks for each core interrupt.
Callbacks for each interrupt will be invoked one by one in interrupt
handler. Core irq will maintain how many times each interrupt has
enabled, and keep it enabled until last disable call is invoked.

Change-Id: I8fe45305fd1bcc8bbdebf3e9ca931842f2c62daf
Signed-off-by: Alan Kwong <akwong@codeaurora.org>
7 files changed