drm/xe/uc: Use managed bo for HuC and GSC objects

drm/xe/uc: Use managed bo for HuC and GSC objects

Drmm actions are not the right ones to clean up BOs and we should use
devm instead. However, we can also instead just allocate the objects
using the managed_bo function, which will internally register the
correct cleanup call and therefore allows us to simplify the code.

While at it, switch to drmm_kzalloc for the GSC proxy allocation to
further simplify the cleanup.

Cc: John Harrison <John.C.Harrison@Intel.com>
Cc: Alan Previn <alan.previn.teres.alexis@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240815230541.3828206-1-lucas.demarchi@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>