Include <sys/mutex.h> and its prerequisite <sys/lock.h> instead of

depending on namespace pollution in <sys/buf.h> and/or <sys/vnode.h>

Approved by:	re (kensmith) (blanket)

sys/fs/msdosfs/msdosfs_vnops.c

@@ -50,7 +50,9 @@
 
 #include <sys/param.h>
 #include <sys/systm.h>
+#include <sys/lock.h>
 #include <sys/lockf.h>
+#include <sys/mutex.h>
 #include <sys/namei.h>
 #include <sys/resourcevar.h>	/* defines plimit structure in proc struct */
 #include <sys/stat.h>