Delete pending list after page flip instead of before
Delete pending list after page flip instead of before

Under certain circumstances the currently displayed frame buffer can be
on the pending deletion list.  If this is deleted then the current crtc
will have no frame buffer and all further attempts to flip buffers will fail.

Popolon/xf86-video-armsoc,commshare/xf86-video-armsoc,commshare/xf86-video-armsoc,Popolon/xf86-video-armsoc