security,bpf: constify struct path in bpf_token_create() LSM hook

There is no reason why struct path pointer shouldn't be const-qualified
when being passed into bpf_token_create() LSM hook. Add that const.

Acked-by: Paul Moore <[e-mail]> (LSM/SELinux)
Suggested-by: Al Viro <[e-mail]>
Signed-off-by: Andrii Nakryiko <[e-mail]>

include/linux/lsm_hook_defs.h

···
 	 struct bpf_token *token)
 LSM_HOOK(void, LSM_RET_VOID, bpf_prog_free, struct bpf_prog *prog)
 LSM_HOOK(int, 0, bpf_token_create, struct bpf_token *token, union bpf_attr *attr,
-	 struct path *path)
+	 const struct path *path)
 LSM_HOOK(void, LSM_RET_VOID, bpf_token_free, struct bpf_token *token)
 LSM_HOOK(int, 0, bpf_token_cmd, const struct bpf_token *token, enum bpf_cmd cmd)
 LSM_HOOK(int, 0, bpf_token_capable, const struct bpf_token *token, int cap)

include/linux/security.h

···
 				  struct bpf_token *token);
 extern void security_bpf_prog_free(struct bpf_prog *prog);
 extern int security_bpf_token_create(struct bpf_token *token, union bpf_attr *attr,
-				     struct path *path);
+				     const struct path *path);
 extern void security_bpf_token_free(struct bpf_token *token);
 extern int security_bpf_token_cmd(const struct bpf_token *token, enum bpf_cmd cmd);
 extern int security_bpf_token_capable(const struct bpf_token *token, int cap);
···
 { }
 
 static inline int security_bpf_token_create(struct bpf_token *token, union bpf_attr *attr,
-				     struct path *path)
+					    const struct path *path)
 {
 	return 0;
 }

security/security.c

···
  * Return: Returns 0 on success, error on failure.
  */
 int security_bpf_token_create(struct bpf_token *token, union bpf_attr *attr,
-			      struct path *path)
+			      const struct path *path)
 {
 	return call_int_hook(bpf_token_create, token, attr, path);
 }

security/selinux/hooks.c

···
 }
 
 static int selinux_bpf_token_create(struct bpf_token *token, union bpf_attr *attr,
-				    struct path *path)
+				    const struct path *path)
 {
 	struct bpf_security_struct *bpfsec;