Commit 'aee3bac0 ("drm/i915/psr: Tie PSR2 support to Y
coordinate requirement")' got merged to drm-intel-next-queued
but the variable was defined commit 'c5fe4732 ("drm: Add PSR
version 3 macro") who was merged through drm-misc.

So backmerging to get drm-intel-next-queued compiling back again.
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>