drm/vc4: bo: Fix drmm_mutex_init memory hog
Commit
374146cad469 ("drm/vc4: Switch to drmm_mutex_init") converted,
among other functions, vc4_create_object() to use drmm_mutex_init().
However, that function is used to allocate a BO, and therefore the
mutex needs to be freed much sooner than when the DRM device is removed
from the system.
For each buffer allocation we thus end up allocating a small structure
as part of the DRM-managed mechanism that is never freed, eventually
leading us to no longer having any free memory anymore.
Let's switch back to mutex_init/mutex_destroy to deal with it properly.
Fixes:
374146cad469 ("drm/vc4: Switch to drmm_mutex_init")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>