ipv6: Rename the dst_cache helper functions in ip6_tunnel

It is a prep work to fix the dst_entry refcnt bugs in
ip6_tunnel.

This patch rename:
1. ip6_tnl_dst_check() to ip6_tnl_dst_get() to better
   reflect that it will take a dst refcnt in the next patch.
2. ip6_tnl_dst_store() to ip6_tnl_dst_set() to have a more
   conventional name matching with ip6_tnl_dst_get().

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip6_tunnel.h

@@ -60,9 +60,9 @@ struct ipv6_tlv_tnl_enc_lim {
 	__u8 encap_limit;	/* tunnel encapsulation limit   */
 } __packed;
 
-struct dst_entry *ip6_tnl_dst_check(struct ip6_tnl *t);
+struct dst_entry *ip6_tnl_dst_get(struct ip6_tnl *t);
 void ip6_tnl_dst_reset(struct ip6_tnl *t);
-void ip6_tnl_dst_store(struct ip6_tnl *t, struct dst_entry *dst);
+void ip6_tnl_dst_set(struct ip6_tnl *t, struct dst_entry *dst);
 int ip6_tnl_rcv_ctl(struct ip6_tnl *t, const struct in6_addr *laddr,
 		const struct in6_addr *raddr);
 int ip6_tnl_xmit_ctl(struct ip6_tnl *t, const struct in6_addr *laddr,