drm/xe/pf: Add top level functions to control VFs

drm/xe/pf: Add top level functions to control VFs

We already have control functions that we use to control the VF
state on the per-GT basis, but that is low level detail from the
user point of view, who rather expects VF-level functions.

For now add simple functions that just iterate over all GTs and
call per-GT control function. We will soon allow to use some of
them from the user facing interfaces like debugfs.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
Link: https://lore.kernel.org/r/20250930233525.201263-2-michal.wajdeczko@intel.com