KEYS: Move the flags representing required permission to linux/key.h

Move the flags representing required permission to linux/key.h as the perm
parameter of security_key_permission() is in terms of them - and not the
permissions mask flags used in key->perm.

Whilst we're at it:

 (1) Rename them to be KEY_NEED_xxx rather than KEY_xxx to avoid collisions
     with symbols in uapi/linux/input.h.

 (2) Don't use key_perm_t for a mask of required permissions, but rather limit
     it to the permissions mask attached to the key and arguments related
     directly to that.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
diff --git a/include/linux/security.h b/include/linux/security.h
index 5623a7f..3a5ed0c 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1707,7 +1707,7 @@
 	void (*key_free) (struct key *key);
 	int (*key_permission) (key_ref_t key_ref,
 			       const struct cred *cred,
-			       key_perm_t perm);
+			       unsigned perm);
 	int (*key_getsecurity)(struct key *key, char **_buffer);
 #endif	/* CONFIG_KEYS */
 
@@ -3026,7 +3026,7 @@
 int security_key_alloc(struct key *key, const struct cred *cred, unsigned long flags);
 void security_key_free(struct key *key);
 int security_key_permission(key_ref_t key_ref,
-			    const struct cred *cred, key_perm_t perm);
+			    const struct cred *cred, unsigned perm);
 int security_key_getsecurity(struct key *key, char **_buffer);
 
 #else
@@ -3044,7 +3044,7 @@
 
 static inline int security_key_permission(key_ref_t key_ref,
 					  const struct cred *cred,
-					  key_perm_t perm)
+					  unsigned perm)
 {
 	return 0;
 }