Unbreak the zfs(4) build

vm/vm_pageout.h grew a dependency on the bool typedef in r300865

arc.c didn't include sys/types.h, which included the definition for the typedef

Other items (ofed, drm2) might need to be chased for this commit.

X-MFC with: r300865
MFC after: 1 week
Pointyhat to: alc
Sponsored by: EMC / Isilon Storage Division

sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c

@@ -120,6 +120,7 @@
  *	- ARC header release, as it removes from L2ARC buflists
  */
 
+#include <sys/types.h>
 #include <sys/spa.h>
 #include <sys/zio.h>
 #include <sys/zio_compress.h>