Revert "drm/i915/userptr: Acquire the page lock around set_page_dirty()"

Revert "drm/i915/userptr: Acquire the page lock around set_page_dirty()"

The userptr put_pages can be called from inside try_to_unmap, and so
enters with the page lock held on one of the object's backing pages. We
cannot take the page lock ourselves for fear of recursion.

Reported-by: Lionel Landwerlin <[email protected]>
Reported-by: Martin Wilck <[email protected]>
Reported-by: Leo Kraav <[email protected]>
Fixes: aa56a292ce62 ("drm/i915/userptr: Acquire the page lock around set_page_dirty()")
References: https://bugzilla.kernel.org/show_bug.cgi?id=203317
Signed-off-by: Chris Wilson <[email protected]>
Cc: Tvrtko Ursulin <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Joonas Lahtinen <[email protected]>
Cc: [email protected]
Signed-off-by: Linus Torvalds <[email protected]>