drm/i915: Document that the pll->mode_set hook is optional

The WRPLLs won't use them.

Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Daniel Vetter 2014-06-25 22:01:58 +03:00
commit 96f6128cbb