usbip: Use min to simplify stub_send_ret_submit

Use min() to improve stub_send_ret_submit(). Change the local variable
'size' from 'int' to 'unsigned int' to prevent a signedness error and to
match the resulting type.

Signed-off-by: Thorsten Blum <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/usbip/stub_tx.c

···
  */
 
 #include <linux/kthread.h>
+#include <linux/minmax.h>
 #include <linux/socket.h>
 #include <linux/scatterlist.h>
 
···
 		    urb->actual_length > 0) {
 			if (urb->num_sgs) {
 				unsigned int copy = urb->actual_length;
-				int size;
+				unsigned int size;
 
 				for_each_sg(urb->sg, sg, urb->num_sgs, i) {
 					if (copy == 0)
 						break;
 
-					if (copy < sg->length)
-						size = copy;
-					else
-						size = sg->length;
-
+					size = min(copy, sg->length);
 					iov[iovnum].iov_base = sg_virt(sg);
 					iov[iovnum].iov_len = size;