drm/i915: Give meaningful names to all the planes

Let's name our planes in a way that makes sense wrt. the spec:
- skl+ -> "plane 1A", "plane 2A", "plane 1C", "cursor A" etc.
- g4x+ -> "primary A", "primary B", "sprite A", "cursor C" etc.
- pre-g4x -> "plane A", "cursor B" etc.

v2: Rebase on top of the fixed/cleaned error paths
    Use a local 'name' variable to make things easier
v3: Pass the name as a function argument to drm_universal_plane_init() (Jani)
v3: Pass the printf style string to drm_universal_plane_init()

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1464371966-15190-6-git-send-email-ville.syrjala@linux.intel.com


Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>