[PATCH] cifs: fix build by selecting CONFIG_KEYS

[Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>]

CONFIG_CIFS_ACL had a dependency "depends on KEYS" which was
dropped with the removal of CONFIG_CIFS_ACL. This breaks the
build on systems which don't have CONFIG_KEYS in .config:

cifsacl.c:37:15: error: variable ‘cifs_idmap_key_acl’ has
                 initializer but incomplete type
   37 | static struct key_acl cifs_idmap_key_acl = {
      |               ^~~~~~~
cifsacl.c:38:3: error: ‘struct key_acl’ has no member
                named ‘usage’
   38 |  .usage = REFCOUNT_INIT(1),
      |   ^~~~~
[..]

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
---
 fs/cifs/Kconfig   | 1 +
 fs/cifs/cifsacl.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/fs/cifs/Kconfig b/fs/cifs/Kconfig
index 3eee73449bdd..5912751e6f09 100644
--- a/fs/cifs/Kconfig
+++ b/fs/cifs/Kconfig
@@ -17,6 +17,7 @@ config CIFS
 	select CRYPTO_ECB
 	select CRYPTO_AES
 	select CRYPTO_DES
+	select KEYS
 	help
 	  This is the client VFS module for the SMB3 family of NAS protocols,
 	  (including support for the most recent, most secure dialect SMB3.1.1)
diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
index 78eed72f3af0..8ca479caf902 100644
--- a/fs/cifs/cifsacl.c
+++ b/fs/cifs/cifsacl.c
@@ -24,6 +24,7 @@
 #include <linux/fs.h>
 #include <linux/slab.h>
 #include <linux/string.h>
+#include <linux/key.h>
 #include <linux/keyctl.h>
 #include <linux/key-type.h>
 #include <keys/user-type.h>
-- 
2.22.0