avutil/ppc/cpu: Use proper header for OpenBSD PPC CPU detection

Use the proper header for PPC CPU detection code. sys/param.h includes
sys/types, but sys/types.h is the more appropriate header to be used
here.

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavutil/ppc/cpu.c

@@ -28,7 +28,7 @@
 #include <unistd.h>
 #endif
 #elif defined(__OpenBSD__)
-#include <sys/param.h>
+#include <sys/types.h>
 #include <sys/sysctl.h>
 #include <machine/cpu.h>
 #elif defined(__AMIGAOS4__)