drm/xe/vf: Fix guc_info debugfs for VFs

The guc_info debugfs attempts to read a bunch of registers that the VFs
doesn't have access to, so fix it by skipping the reads.

Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/4775


Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Lukasz Laguna <lukasz.laguna@intel.com>
Reviewed-by: Lukasz Laguna <lukasz.laguna@intel.com>
Link: https://lore.kernel.org/r/20250423173908.1571412-1-daniele.ceraolospurio@intel.com