usb: gadget: mbim: Change message level from error to debug

Change level of message to prevent excessive logging and
increase mbim throughput from 800 KB/s to 3 MB/s.

Change-Id: Iffec43825c90c8cb5838f9879342e9a021ef087b
Signed-off-by: Anna Perel <aperel@codeaurora.org>
diff --git a/drivers/usb/gadget/f_mbim.c b/drivers/usb/gadget/f_mbim.c
index daa981f..27781b8 100644
--- a/drivers/usb/gadget/f_mbim.c
+++ b/drivers/usb/gadget/f_mbim.c
@@ -1674,7 +1674,7 @@
 	}
 
 	while (list_empty(&dev->cpkt_req_q)) {
-		pr_err("Requests list is empty. Wait.\n");
+		pr_debug("Requests list is empty. Wait.\n");
 		ret = wait_event_interruptible(dev->read_wq,
 			!list_empty(&dev->cpkt_req_q));
 		if (ret < 0) {