drm/i915: Clear the in-use marker on execbuf failure

drm/i915: Clear the in-use marker on execbuf failure

If we fail to unbind the vma (due to a signal on an active buffer that
needs to be moved for the next execbuf), then we need to clear the
persistent tracking state we setup for this execbuf.

Fixes: c7c6e46f913b ("drm/i915: Convert execbuf to use struct-of-array packing for critical fields")
Testcase: igt/gem_fenced_exec_thrash/no-spare-fences-busy*
Signed-off-by: Chris Wilson <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Joonas Lahtinen <[email protected]>
Cc: <[email protected]> # v4.14+
Reviewed-by: Tvrtko Ursulin <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
(cherry picked from commit ed2f3532321083cf40e4da4e36234880e0136136)
Signed-off-by: Rodrigo Vivi <[email protected]>