Remove some unnecessary includes

alc/mixer/mixer_neon.cpp

@@ -4,14 +4,9 @@
 
 #include <limits>
 
-#include "AL/al.h"
-#include "AL/alc.h"
-#include "alcmain.h"
 #include "alnumeric.h"
-#include "alu.h"
-#include "hrtf.h"
-#include "defs.h"
 #include "bsinc_defs.h"
+#include "defs.h"
 #include "hrtfbase.h"
 
 struct NEONTag;

alc/mixer/mixer_sse.cpp

@@ -4,11 +4,7 @@
 
 #include <limits>
 
-#include "AL/al.h"
-#include "AL/alc.h"
-#include "alcmain.h"
-
-#include "alu.h"
+#include "alnumeric.h"
 #include "bsinc_defs.h"
 #include "defs.h"
 #include "hrtfbase.h"

alc/mixer/mixer_sse2.cpp

@@ -24,7 +24,6 @@
 #include <emmintrin.h>
 
 #include "alnumeric.h"
-#include "alu.h"
 #include "defs.h"
 
 struct SSE2Tag;

alc/mixer/mixer_sse41.cpp

@@ -25,7 +25,6 @@
 #include <smmintrin.h>
 
 #include "alnumeric.h"
-#include "alu.h"
 #include "defs.h"
 
 struct SSE4Tag;