kms_plane: Make the gathering of reference CRCs test agnostic

We're going to add tests for panning. Both position and panning tests
share the need to grab reference CRCs of single coloured fb, so let's
separate this function from the position test.

Cc: Lei Liu <lei.a.liu@intel.com>
Cc: Yi Sun <yi.sun@intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
1 file changed