fs: convert simple fs to new truncate

Convert simple filesystems: ramfs, configfs, sysfs, block_dev to new truncate
sequence.

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ramfs/file-mmu.c b/fs/ramfs/file-mmu.c
index 5002050..4884ac5 100644
--- a/fs/ramfs/file-mmu.c
+++ b/fs/ramfs/file-mmu.c
@@ -50,5 +50,6 @@
 };
 
 const struct inode_operations ramfs_file_inode_operations = {
+	.setattr	= simple_setattr,
 	.getattr	= simple_getattr,
 };