lockdep: Swap storage for pin_count and references

As a lockmap takes a reference for every ww_mutex used together, this
can be an arbitrarily large number and under control of userspace --
easily overflowing the arbitrary limit of 4096. However, the pin_count
(used for detecting unexpected lock dropping) is a full 32b despite
nesting being extremely rare (see lockdep_pin_lock).

References: https://gitlab.freedesktop.org/drm/intel/-/issues/8028


Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190425092004.9995-33-chris@chris-wilson.co.uk


Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
[Joonas: Converting to pin_count:11 as per addition of sync:1]
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>