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>

fs/ramfs/file-mmu.c

@@ -50,5 +50,6 @@ const struct file_operations ramfs_file_operations = {
 };
 
 const struct inode_operations ramfs_file_inode_operations = {
+	.setattr	= simple_setattr,
 	.getattr	= simple_getattr,
 };