sanitize linux/isdn_divertif.h for userspace

the isdn_divertif contains kernel-only references so I've wrapped them in
__KERNEL__ and add proper #include statements.

Signed-off-by: Mike Frysinger <[e-mail]>
Cc: Karsten Keil <[e-mail]>
Cc: David Woodhouse <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

include/linux/Kbuild

···
 header-y += ipsec.h
 header-y += ipx.h
 header-y += irda.h
-header-y += isdn_divertif.h
 header-y += iso_fs.h
 header-y += ixjuser.h
 header-y += jffs2.h
···
 unifdef-y += ipv6_route.h
 unifdef-y += isdn.h
 unifdef-y += isdnif.h
+unifdef-y += isdn_divertif.h
 unifdef-y += isdn_ppp.h
 unifdef-y += isicom.h
 unifdef-y += jbd.h

include/linux/isdn_divertif.h

···
 #define DIVERT_REL_ERR  0x04  /* module not registered */
 #define DIVERT_REG_NAME isdn_register_divert
 
+#ifdef __KERNEL__
+#include <linux/isdnif.h>
+#include <linux/types.h>
+
 /***************************************************************/
 /* structure exchanging data between isdn hl and divert module */
 /***************************************************************/ 
···
 /* function register */
 /*********************/
 extern int DIVERT_REG_NAME(isdn_divert_if *);
+#endif