staging: r8712u: fix control-message timeout

USB control-message timeouts are specified in milliseconds and should
specifically not vary with CONFIG_HZ.

Fixes: 2865d42c78a9 ("staging: r8712u: Add the new driver to the mainline kernel")
Cc: [e-mail] # 2.6.37
Acked-by: Larry Finger <[e-mail]>
Signed-off-by: Johan Hovold <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/rtl8712/usb_ops_linux.c

···
 		memcpy(pIo_buf, pdata, len);
 	}
 	status = usb_control_msg(udev, pipe, request, reqtype, value, index,
-				 pIo_buf, len, HZ / 2);
+				 pIo_buf, len, 500);
 	if (status > 0) {  /* Success this control transfer. */
 		if (requesttype == 0x01) {
 			/* For Control read transfer, we have to copy the read