Enable an activity masking of PVQ

By default, the activity masking is used with PVQ.
In addition to '--enable-pvq', '--enable-daala-dist' is also
required by configure to use the activity masking.

Change-Id: I5100a1db992f0e693e61daf5439de8ae8c64a752

av1/common/pvq.h

diff --git a/av1/common/pvq.h b/av1/common/pvq.h
index d1f2596..9afe65f 100644
--- a/av1/common/pvq.h
+++ b/av1/common/pvq.h
@@ -19,9 +19,9 @@
 extern const uint16_t EXP_CDF_TABLE[][16];
 extern const uint16_t LAPLACE_OFFSET[];
 
-#define AV1_PVQ_ENABLE_ACTIVITY_MASKING (0)
-
-#if !CONFIG_DAALA_DIST
+#if CONFIG_DAALA_DIST
+#define AV1_PVQ_ENABLE_ACTIVITY_MASKING (1)
+#else
 #define AV1_PVQ_ENABLE_ACTIVITY_MASKING (0)
 #endif