ACPI: update feature-removal.txt to reflect deleted acpi=ht option

Per plan, acpi=ht was removed in 2.6.35-rc1.
Signed-off-by: Len Brown <len.brown@intel.com>

Documentation/feature-removal-schedule.txt

@@ -578,15 +578,6 @@ Who:	Avi Kivity <avi@redhat.com>
 
 ----------------------------
 
-What: 	"acpi=ht" boot option
-When:	2.6.35
-Why:	Useful in 2003, implementation is a hack.
-	Generally invoked by accident today.
-	Seen as doing more harm than good.
-Who:	Len Brown <len.brown@intel.com>
-
-----------------------------
-
 What:	iwlwifi 50XX module parameters
 When:	2.6.40
 Why:	The "..50" modules parameters were used to configure 5000 series and