drm/xe: Move SR-IOV probe to xe_device_probe_early()

SR-IOV mode detection requires access to the MMIO register and
this can be done now in xe_device_probe_early().

We can also drop explicit has_sriov parameter as this flag is now
already available from xe->info.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240327182740.407-3-michal.wajdeczko@intel.com