gralloc: hdmi cloned mode support

Patch implements simple support for cloned mode hdmi by introducing
primary and hdmi outputs that are updated respectively.

Current implementation is rather naive and assumes hdmi can drive
same mode as the local lvds. Only cloned mode is supported but can be
extended later to support extended mode when hwcomposer is available
for controlling this behaviour.

HDMI hotplug is implemented as a separate observer thread that
listens to uevents and reads hdmi connection state from there, this
requires switch support from the kernel hdmi driver.

Change-Id: I147273bbe4d21ab9f390f38c9a5f945530c8fd2e
Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Signed-off-by: Matt Gumbel <matthew.k.gumbel@linux.intel.com>
4 files changed