Move swblk_t from sys/types.h to sys/dmap.h, the only include that uses

it.  It's also only used in vm/vm_swap.c, but that is also the only source
file that #include's <sys/dmap.h>.  sys/dmap.h could probably be embedded
entirely in vm_swap.c since that is the only consumer of it.

sys/sys/dmap.h

@@ -37,6 +37,8 @@
 #ifndef _SYS_DMAP_H_
 #define	_SYS_DMAP_H_
 
+typedef	int32_t	swblk_t;	/* swap offset */
+
 /*
  * Definitions for the mapping of vitual swap space to the physical swap
  * area - the disk map.

sys/sys/types.h

@@ -150,7 +150,6 @@ typedef	__pid_t		pid_t;		/* process id */
 typedef	__register_t	register_t;
 typedef	__int64_t	rlim_t;		/* resource limit (XXX not unsigned) */
 typedef	__segsz_t	segsz_t;	/* segment size (in pages) */
-typedef	__int32_t	swblk_t;	/* swap offset */
 typedef	__u_register_t	u_register_t;
 
 #ifndef _UID_T_DECLARED