drm/xe/eustall: Do not support EU stall on SRIOV VF

EU stall sampling is not supported on SRIOV VF. Do not
initialize or open EU stall stream on SRIOV VF.

Fixes: 9a0b11d4 ("drm/xe/eustall: Add support to init, enable and disable EU stall sampling")
Signed-off-by: Harish Chegondi <harish.chegondi@intel.com>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://lore.kernel.org/r/10db5d1c7e17aadca7078ff74575b7ffc0d5d6b8.1745215022.git.harish.chegondi@intel.com