drm/i915/mtl: Update workaround 14018575942

The WA should be extended to cover VDBOX engine. We found that
28-channels 1080p VP9 encoding may hit this issue.

v3: update the WA number and explain the reason why
    this workaround is needed
v2: add WA number
v1: initial version

Signed-off-by: Angus Chen <angus.chen@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240426073638.45775-1-angus.chen@intel.com

drivers/gpu/drm/i915/gt/intel_workarounds.c

@@ -1590,6 +1590,14 @@ xelpmp_gt_workarounds_init(struct intel_gt *gt, struct i915_wa_list *wal)
 	 */
 	wa_write_or(wal, XELPMP_GSC_MOD_CTRL, FORCE_MISS_FTLB);
 
+	/*
+	 * Wa_14018575942
+	 *
+	 * Issue is seen on media KPI test running on VDBOX engine
+	 * especially VP9 encoding WLs
+	 */
+	wa_write_or(wal, XELPMP_VDBX_MOD_CTRL, FORCE_MISS_FTLB);
+
 	/* Wa_22016670082 */
 	wa_write_or(wal, GEN12_SQCNT1, GEN12_STRICT_RAR_ENABLE);