mei: samples: fix a signedness bug in amt_host_if_call()

"out_buf_sz" needs to be signed for the error handling to work.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

samples/mei/mei-amt-version.c

@@ -370,7 +370,7 @@ static uint32_t amt_host_if_call(struct amt_host_if *acmd,
 			unsigned int expected_sz)
 {
 	uint32_t in_buf_sz;
-	uint32_t out_buf_sz;
+	ssize_t out_buf_sz;
 	ssize_t written;
 	uint32_t status;
 	struct amt_host_if_resp_header *msg_hdr;