apparmor: rename SK_CTX() to aa_sock and make it an inline fn

In preparation for LSM stacking rework the macro to an inline fn

Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>

security/apparmor/include/net.h

@@ -52,6 +52,11 @@ struct aa_sk_ctx {
 };
 
 #define SK_CTX(X) ((X)->sk_security)
+static inline struct aa_sk_ctx *aa_sock(const struct sock *sk)
+{
+	return sk->sk_security;
+}
+
 #define DEFINE_AUDIT_NET(NAME, OP, SK, F, T, P)				  \
 	struct lsm_network_audit NAME ## _net = { .sk = (SK),		  \
 						  .family = (F)};	  \