drm/i915/tgl: Fix the Wa number of a fix

The Wa number for this fix is Wa_1607087056 the BSpec bug id is
1607087056, just updating to match BSpec.

BSpec: 52890
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200227220101.321671-7-jose.souza@intel.com

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

@@ -931,7 +931,7 @@ tgl_gt_workarounds_init(struct drm_i915_private *i915, struct i915_wa_list *wal)
 			    SUBSLICE_UNIT_LEVEL_CLKGATE2,
 			    CPSSUNIT_CLKGATE_DIS);
 
-	/* Wa_1409180338:tgl */
+	/* Wa_1607087056:tgl also know as BUG:1409180338 */
 	if (IS_TGL_REVID(i915, TGL_REVID_A0, TGL_REVID_A0))
 		wa_write_or(wal,
 			    SLICE_UNIT_LEVEL_CLKGATE,