ppc: Add some missing headers

libavcodec/ppc/dsputil_altivec.c

@@ -27,6 +27,7 @@
 #include "libavutil/attributes.h"
 #include "libavutil/ppc/types_altivec.h"
 #include "libavutil/ppc/util_altivec.h"
+#include "libavcodec/avcodec.h"
 #include "libavcodec/dsputil.h"
 #include "dsputil_altivec.h"
 

libavcodec/ppc/dsputil_ppc.c

@@ -26,6 +26,8 @@
 #include "libavutil/cpu.h"
 #include "libavutil/mem.h"
 #include "libavutil/ppc/cpu.h"
+#include "libavcodec/avcodec.h"
+#include "libavcodec/dsputil.h"
 #include "dsputil_altivec.h"
 
 /* ***** WARNING ***** WARNING ***** WARNING ***** */

libavcodec/ppc/vc1dsp_altivec.c

@@ -21,6 +21,7 @@
 
 #include "config.h"
 #include "libavutil/attributes.h"
+#include "libavutil/cpu.h"
 #include "libavutil/ppc/types_altivec.h"
 #include "libavutil/ppc/util_altivec.h"
 #include "libavcodec/vc1dsp.h"