EDP: update documentation

Adding documentation about debugfs features and tegra specific
implementation.

Change-Id: I087391b522ee89cfe7a75ad44c4ea005c139c1b2
Signed-off-by: Sivaram Nair <sivaramn@nvidia.com>
Reviewed-on: http://git-master/r/204195
Reviewed-by: Juha Tukkinen <jtukkinen@nvidia.com>
2 files changed