af_key: fix indentation on declaration statement

There is an indentation issue before the declaration of xfrm_ctx. Remove
spaces and replace with a tab.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

net/key/af_key.c

@@ -2020,7 +2020,7 @@ parse_ipsecrequests(struct xfrm_policy *xp, struct sadb_x_policy *pol)
 
 static inline int pfkey_xfrm_policy2sec_ctx_size(const struct xfrm_policy *xp)
 {
-  struct xfrm_sec_ctx *xfrm_ctx = xp->security;
+	struct xfrm_sec_ctx *xfrm_ctx = xp->security;
 
 	if (xfrm_ctx) {
 		int len = sizeof(struct sadb_x_sec_ctx);