post_proc: clean up stale audiosphere implementation

Now that we have GEF based implementation, clean up stale one.

CRs-Fixed: 2484430
Change-Id: I7dcad43401650c51e637fce202f5b45d40b3852e
diff --git a/post_proc/Android.mk b/post_proc/Android.mk
index 6b1afd3..fb42514 100644
--- a/post_proc/Android.mk
+++ b/post_proc/Android.mk
@@ -30,8 +30,7 @@
         virtualizer.c \
         reverb.c \
         effect_api.c \
-        effect_util.c \
-        asphere.c
+        effect_util.c
 
 # HW_ACCELERATED has been disabled by default since msm8996. File doesn't
 # compile cleanly on tip so don't want to include it, but keeping this