misc: mei: client.c: fix problem of return '-EOVERFLOW' in mei_cl_write

Clang static analyzer complains that value stored to 'rets' is never
read.Let 'buf_len = -EOVERFLOW' to make sure we can return '-EOVERFLOW'.

Fixes: 8c8d964ce90f ("mei: move hbuf_depth from the mei device to the hw modules")
Signed-off-by: Su Hui <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/misc/mei/client.c

···
 
 	hbuf_slots = mei_hbuf_empty_slots(dev);
 	if (hbuf_slots < 0) {
-		rets = -EOVERFLOW;
+		buf_len = -EOVERFLOW;
 		goto out;
 	}