Attempt to fix the build.

On targets without neon it looks like
idct_blk.c is needed to provide some symbols
that come from NEON optimized ASM.

Change-Id: I223071ce60ca7fde59160854fc1a71211f049a81
diff --git a/Android.mk b/Android.mk
index 8af6e5e..a475016 100644
--- a/Android.mk
+++ b/Android.mk
@@ -51,7 +51,7 @@
     vp8/decoder/threading.c \
     vp8/vp8_dx_iface.c \
     vpx_config.c \
-    vp8/decoder/arm/neon/idct_blk_neon.c \
+    vp8/decoder/arm/neon/idct_blk_neon.c
 
 LOCAL_CFLAGS := \
     -DHAVE_CONFIG_H=vpx_config.h
@@ -114,6 +114,10 @@
 
 LOCAL_GENERATED_SOURCES += $(VPX_GEN)
 
+else
+
+LOCAL_SRC_FILES += vp8/decoder/idct_blk.c
+
 endif
 
 LOCAL_C_INCLUDES := \