drm/i915: Move CUR SURFLIVE definition to a better place.

No functional change. But let's keep definitions clean
and cursor related register definitions together.

v2: Fix caps x no caps on same reg. Change name to match
    original reg name. (by Ville).
    Also fix name on code s/surlive/surflive and on subject
    s/cur_surlife/cur surflive/.

Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180312210528.7905-1-rodrigo.vivi@intel.com