drm/i915: Make GEM object alloc/free and stolen created take dev_priv

Where it is more appropriate and also to be consistent with
the direction of the driver.

v2: Leave out object alloc/free inlining. (Joonas Lahtinen)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
12 files changed