openvswitch: Rename GENEVE_TUN_OPTS() to TUN_METADATA_OPTS()

Also factors out Geneve validation code into a new separate function
validate_and_copy_geneve_opts().

A subsequent patch will introduce VXLAN options. Rename the existing
GENEVE_TUN_OPTS() to reflect its extended purpose of carrying generic
tunnel metadata options.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c
index df334fe..e2c348b 100644
--- a/net/openvswitch/flow.c
+++ b/net/openvswitch/flow.c
@@ -691,7 +691,7 @@
 			BUILD_BUG_ON((1 << (sizeof(tun_info->options_len) *
 						   8)) - 1
 					> sizeof(key->tun_opts));
-			memcpy(GENEVE_OPTS(key, tun_info->options_len),
+			memcpy(TUN_METADATA_OPTS(key, tun_info->options_len),
 			       tun_info->options, tun_info->options_len);
 			key->tun_opts_len = tun_info->options_len;
 		} else {