drm/i915/psr/cnl: Enable Y-coordinate support in source

For Geminilake and Cannonlake+ the Y-coordinate support must be
enabled in PSR2_CTL too.

Spec: 7713 and 7720

Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180328223046.16125-5-jose.souza@intel.com