drm: Have the crtc code only reference master from legacy nodes v2
drm: Have the crtc code only reference master from legacy nodes v2

control- and render nodes are intended to be master-less.

v2: Replace tests for !legacy with tests for !mode_group for readability.

Signed-off-by: Thomas Hellstrom <a26490dfbee4be3d38287ad6448444504f58193c@vmware.com>
Reviewed-by: David Herrmann <fb53b2ddb8d141e0cb39d7c67c2f81b6bc2eb0f7@gmail.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs