[Intel-gfx] [PATCH i-g-t 0/2] kms_flip: Test for page flip crtc->fb clobber bug

[ville.syrjala at linux.intel.com]

This new test 'flip-vs-bad-tiling' will trigger the pin_count underflow
BUG in the kernel due to page flip clobbering the crtc->fb pointer when
queue_flip fails. With the kernel fix applied the test completes
succesfully.

I also included a small fix for a use-after-free bug I spotted.