Explicitly include SPL compat headers

Inclusion of SPL compatibility headers was moved out of the public
header sys/types.h to avoid conflicts with external packages.  Include a
few compatiblity headers explicitly to cope with that change.  Also,
sort some linux-specific inclusions alphabetically.

Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2898

module/zfs/arc.c

@@ -140,6 +140,7 @@
 #include <vm/anon.h>
 #include <sys/fs/swapnode.h>
 #include <sys/zpl.h>
+#include <linux/mm_compat.h>
 #endif
 #include <sys/callb.h>
 #include <sys/kstat.h>

module/zfs/zfs_ioctl.c

@@ -186,6 +186,7 @@
 #include <sys/zfeature.h>
 
 #include <linux/miscdevice.h>
+#include <linux/module_compat.h>
 
 #include "zfs_namecheck.h"
 #include "zfs_prop.h"