usbnet: fix memory allocation in helpers

usbnet provides some helper functions that are also used in
the context of reset() operations. During a reset the other
drivers on a device are unable to operate. As that can be block
drivers, a driver for another interface cannot use paging
in its memory allocations without risking a deadlock.
Use GFP_NOIO in the helpers.

Fixes: 877bd862 ("usbnet: introduce usbnet 3 command helpers")
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Link: https://lore.kernel.org/r/20220628093517.7469-1-oneukum@suse.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/usb/usbnet.c

@@ -2004,7 +2004,7 @@ static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
 		   cmd, reqtype, value, index, size);
 
 	if (size) {
-		buf = kmalloc(size, GFP_KERNEL);
+		buf = kmalloc(size, GFP_NOIO);
 		if (!buf)
 			goto out;
 	}
@@ -2036,7 +2036,7 @@ static int __usbnet_write_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
 		   cmd, reqtype, value, index, size);
 
 	if (data) {
-		buf = kmemdup(data, size, GFP_KERNEL);
+		buf = kmemdup(data, size, GFP_NOIO);
 		if (!buf)
 			goto out;
 	} else {