MFC:	sys/kern/vfs_subr.c	1.682
MFC:	sys/kern/vfs_subr.c	1.682

Add 'show vnode <addr>' DDB command.

Requested by:	kib

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase