vm_object: Widen the flags field

Take advantage of a nearby 2-byte hole to avoid growing the struct.
This way, only the offsets of "flags" and "pg_color" change.  Bump
__FreeBSD_version since some out-of-tree kernel modules may access these
fields, though I haven't found any examples so far.

Reviewed by:	kib
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D35905

sys/sys/param.h

@@ -73,7 +73,7 @@
  * cannot include sys/param.h and should only be updated here.
  */
 #undef __FreeBSD_version
-#define __FreeBSD_version 1500024
+#define __FreeBSD_version 1500025
 
 /*
  * __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,

sys/vm/vm_object.h

@@ -108,8 +108,8 @@ struct vm_object {
 	int shadow_count;		/* how many objects that this is a shadow for */
 	vm_memattr_t memattr;		/* default memory attribute for pages */
 	objtype_t type;			/* type of pager */
-	u_short flags;			/* see below */
 	u_short pg_color;		/* (c) color of first page in obj */
+	u_int flags;			/* see below */
 	blockcount_t paging_in_progress; /* (a) Paging (in or out) so don't collapse or destroy */
 	blockcount_t busy;		/* (a) object is busy, disallow page busy. */
 	int resident_page_count;	/* number of resident pages */