fs: nfs: add missing MODULE_DESCRIPTION() macros

Fix the 'make W=1' warnings:
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nfs_common/nfs_acl.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nfs_common/grace.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nfs/nfs.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nfs/nfsv2.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nfs/nfsv3.o
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/nfs/nfsv4.o

Signed-off-by: Jeff Johnson <[e-mail]>
Reviewed-by: Jeff Layton <[e-mail]>
Signed-off-by: Anna Schumaker <[e-mail]>

fs/nfs/inode.c

···
 
 /* Not quite true; I just maintain it */
 MODULE_AUTHOR("Olaf Kirch <[e-mail]>");
+MODULE_DESCRIPTION("NFS client support");
 MODULE_LICENSE("GPL");
 module_param(enable_ino64, bool, 0644);
 

fs/nfs/nfs2super.c

···
 	unregister_nfs_version(&nfs_v2);
 }
 
+MODULE_DESCRIPTION("NFSv2 client support");
 MODULE_LICENSE("GPL");
 
 module_init(init_nfs_v2);

fs/nfs/nfs3super.c

···
 	unregister_nfs_version(&nfs_v3);
 }
 
+MODULE_DESCRIPTION("NFSv3 client support");
 MODULE_LICENSE("GPL");
 
 module_init(init_nfs_v3);

fs/nfs/nfs4super.c

···
 	nfs_dns_resolver_destroy();
 }
 
+MODULE_DESCRIPTION("NFSv4 client support");
 MODULE_LICENSE("GPL");
 
 module_init(init_nfs_v4);

fs/nfs_common/grace.c

···
 }
 
 MODULE_AUTHOR("Jeff Layton <[e-mail]>");
+MODULE_DESCRIPTION("NFS client and server infrastructure");
 MODULE_LICENSE("GPL");
 module_init(init_grace)
 module_exit(exit_grace)

fs/nfs_common/nfsacl.c

···
 #include <linux/nfs3.h>
 #include <linux/sort.h>
 
+MODULE_DESCRIPTION("NFS ACL support");
 MODULE_LICENSE("GPL");
 
 struct nfsacl_encode_desc {