NFS: Remove CONFIG_NFS_V4 checks from nfs_idmap.h

The idmapper is completely internal to the NFS v4 module, so this macro
will always evaluate to true.  This patch also removes unnecessary
includes of this file from the generic NFS client.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/client.c

@@ -31,7 +31,6 @@
 #include <linux/lockd/bind.h>
 #include <linux/seq_file.h>
 #include <linux/mount.h>
-#include <linux/nfs_idmap.h>
 #include <linux/vfs.h>
 #include <linux/inet.h>
 #include <linux/in6.h>

fs/nfs/super.c

@@ -43,7 +43,6 @@
 #include <linux/seq_file.h>
 #include <linux/mount.h>
 #include <linux/namei.h>
-#include <linux/nfs_idmap.h>
 #include <linux/vfs.h>
 #include <linux/inet.h>
 #include <linux/in6.h>

include/linux/nfs_idmap.h

@@ -46,19 +46,8 @@ struct nfs_server;
 struct nfs_fattr;
 struct nfs4_string;
 
-#if IS_ENABLED(CONFIG_NFS_V4)
 int nfs_idmap_init(void);
 void nfs_idmap_quit(void);
-#else
-static inline int nfs_idmap_init(void)
-{
-	return 0;
-}
-
-static inline void nfs_idmap_quit(void)
-{}
-#endif
-
 int nfs_idmap_new(struct nfs_client *);
 void nfs_idmap_delete(struct nfs_client *);