Remove obsolete comment

Change-Id: Iad2e9fb5e027a15a4d928f988579de1021cea996

av1/common/filter.h

diff --git a/av1/common/filter.h b/av1/common/filter.h
index a604cfe..44d8d20 100644
--- a/av1/common/filter.h
+++ b/av1/common/filter.h
@@ -44,12 +44,9 @@
   USE_8_TAPS,
 } SUBPEL_SEARCH_TYPE;
 
-// With CONFIG_DUAL_FILTER, pack two InterpFilter's into a uint32_t: since
-// there are at most 10 filters, we can use 16 bits for each and have more than
-// enough space. This reduces argument passing and unifies the operation of
-// setting a (pair of) filters.
-//
-// Without CONFIG_DUAL_FILTER,
+// Pack two InterpFilter's into a uint32_t: since there are at most 10 filters,
+// we can use 16 bits for each and have more than enough space. This reduces
+// argument passing and unifies the operation of setting a (pair of) filters.
 typedef uint32_t InterpFilters;
 static INLINE InterpFilter av1_extract_interp_filter(InterpFilters filters,
                                                      int x_filter) {