[proto] Remove unsupported NFS protocol

The NFS protocol code came from legacy Etherboot and was never updated
to work as a gPXE protocol.  There has been no demand for this protocol,
so this patch removes it.

I have an unfinished NFSv3 over TCP implementation for gPXE that can be
used as the base for new work, should we want to resurrect this
protocol.

Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Marty Connor <mdc@etherboot.org>

src/core/settings.c

@@ -1426,7 +1426,7 @@ struct setting filename_setting __setting = {
 /** Root path setting */
 struct setting root_path_setting __setting = {
 	.name = "root-path",
-	.description = "NFS/iSCSI root path",
+	.description = "iSCSI root path",
 	.tag = DHCP_ROOT_PATH,
 	.type = &setting_type_string,
 };