drm/xe/vf: Don't check CTC_MODE[0] if VF

Starting from commit 18778b5 ("drm/xe: Eliminate usage of
TIMESTAMP_OVERRIDE") we access the CTC_MODE register only to warn
if it has undocumented value.  There is no point in doing that on
the VF driver.  While here, move this check to a helper function.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250311114042.1954-2-michal.wajdeczko@intel.com

drivers/gpu/drm/xe/xe_gt_clock.c

@@ -40,11 +40,8 @@ static u32 get_crystal_clock_freq(u32 rpm_config_reg)
 	}
 }
 
-int xe_gt_clock_init(struct xe_gt *gt)
+static void check_ctc_mode(struct xe_gt *gt)
 {
-	u32 c0 = xe_mmio_read32(&gt->mmio, RPM_CONFIG0);
-	u32 freq = 0;
-
 	/*
 	 * CTC_MODE[0] = 1 is definitely not supported for Xe2 and later
 	 * platforms.  In theory it could be a valid setting for pre-Xe2
@@ -57,7 +54,17 @@ int xe_gt_clock_init(struct xe_gt *gt)
 	 */
 	if (xe_mmio_read32(&gt->mmio, CTC_MODE) & CTC_SOURCE_DIVIDE_LOGIC)
 		xe_gt_warn(gt, "CTC_MODE[0] is set; this is unexpected and undocumented\n");
+}
+
+int xe_gt_clock_init(struct xe_gt *gt)
+{
+	u32 freq;
+	u32 c0;
+
+	if (!IS_SRIOV_VF(gt_to_xe(gt)))
+		check_ctc_mode(gt);
 
+	c0 = xe_mmio_read32(&gt->mmio, RPM_CONFIG0);
 	freq = get_crystal_clock_freq(c0);
 
 	/*