vpxenc: fix DECODER ifdef

CONFIG_VP10_ENCODER -> CONFIG_VP10_DECODER

Change-Id: I6f1a798835acc4ef66bd2c5d6ffb02247c74b1d6
diff --git a/vpxenc.c b/vpxenc.c
index d83ffb7..06604ea 100644
--- a/vpxenc.c
+++ b/vpxenc.c
@@ -35,7 +35,7 @@
 #if CONFIG_VP8_ENCODER || CONFIG_VP9_ENCODER || CONFIG_VP10_ENCODER
 #include "vpx/vp8cx.h"
 #endif
-#if CONFIG_VP8_DECODER || CONFIG_VP9_DECODER || CONFIG_VP10_ENCODER
+#if CONFIG_VP8_DECODER || CONFIG_VP9_DECODER || CONFIG_VP10_DECODER
 #include "vpx/vp8dx.h"
 #endif