fs: fix kernel_read prototype

Use proper ssize_t and size_t types for the return value and count
argument, move the offset last and make it an in/out argument like
all other read/write helpers, and make the buf argument a void pointer
to get rid of lots of casts in the callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

drivers/mtd/nand/nandsim.c

@@ -1379,7 +1379,7 @@ static ssize_t read_file(struct nandsim *ns, struct file *file, void *buf, size_
 	if (err)
 		return err;
 	noreclaim_flag = memalloc_noreclaim_save();
-	tx = kernel_read(file, pos, buf, count);
+	tx = kernel_read(file, buf, count, &pos);
 	memalloc_noreclaim_restore(noreclaim_flag);
 	put_pages(ns);
 	return tx;