Move MAP_32BIT_MAX_ADDR definition to sys/mman.h.

Reviewed by:	markj
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D24652

sys/sys/mman.h

@@ -296,6 +296,9 @@ void	shm_drop(struct shmfd *shmfd);
 int	shm_dotruncate(struct shmfd *shmfd, off_t length);
 
 extern struct fileops shm_ops;
+
+#define	MAP_32BIT_MAX_ADDR	((vm_offset_t)1 << 31)
+
 #else /* !_KERNEL */
 
 __BEGIN_DECLS

sys/vm/vm_map.c

@@ -1913,8 +1913,6 @@ SYSCTL_LONG(_vm, OID_AUTO, aslr_restarts, CTLFLAG_RD,
     &aslr_restarts, 0,
     "Number of aslr failures");
 
-#define	MAP_32BIT_MAX_ADDR	((vm_offset_t)1 << 31)
-
 /*
  * Searches for the specified amount of free space in the given map with the
  * specified alignment.  Performs an address-ordered, first-fit search from