drm/xe/vf: Avoid reading media version when media GT is disabled

When the media GT is not allowed, a VF must not attempt to read
the media version from the GuC. The GuC may not be loaded, and
any attempt to communicate with it would result in a timeout
and a VF probe failure:

(...)
[ 1912.406046] xe 0000:01:00.1: [drm] *ERROR* Tile0: GT1: GuC mmio request 0x5507: no reply 0x5507
[ 1912.407277] xe 0000:01:00.1: [drm] *ERROR* Tile0: GT1: [GUC COMMUNICATION] MMIO send failed (-ETIMEDOUT)
[ 1912.408689] xe 0000:01:00.1: [drm] *ERROR* VF: Tile0: GT1: Failed to reset GuC state (-ETIMEDOUT)
[ 1912.413986] xe 0000:01:00.1: probe with driver xe failed with error -110

Let's skip reading the media version for VFs when the media GT is not
allowed.

v2: move the condition directly to the VF path

Fixes: 7abd69278bb5 ("drm/xe/configfs: Add attribute to disable GT types")
Signed-off-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Shuicheng Lin <shuicheng.lin@intel.com>
Reviewed-by: Shuicheng Lin <shuicheng.lin@intel.com>
Link: https://patch.msgid.link/20260202115041.2863357-1-piotr.piorkowski@intel.com
Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
(cherry picked from commit 0bcacf56dc0b265f9c47056c6a4f0c1394a8a3f0)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>