drm/i915: add pipe/plane enable/disable functions

Add plane enable/disable functions to prevent duplicated code and allow
us to easily check for plane enable/disable requirements (such as pipe
enable, plane status, pll status etc).

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
2 files changed