usb: configfs: Reset the use_os_desc flag

os_desc support can be turned off via userspace. Kernel also
needs to correspondingly reset its state if userspace has changed
it. Otherwise this cause os descs to be advertised on drivers that
have no os desc support.

Change-Id: Ib8da2eb78a1640aac9abdb29840a33773603d1a8
Signed-off-by: Ravi Vembu <raviv@motorola.com>
Moto-CRs-fixed: (CR)
Reviewed-on: https://gerrit.mot.com/920122
SLTApproved: Slta Waiver <sltawvr@motorola.com>
SME-Granted: SME Approvals Granted
Tested-by: Jira Key <jirakey@motorola.com>
Reviewed-by: Christopher Fries <cfries@motorola.com>
Submit-Approved: Jira Key <jirakey@motorola.com>
Reviewed-on: https://gerrit.mot.com/1167316
SLTApproved: Slta Waiver
Tested-by: Jira Key
Reviewed-by: Lu Chai <chailu1@motorola.com>
Reviewed-by: Jianqi Yang <yangj@motorola.com>
Submit-Approved: Jira Key
Reviewed-on: https://gerrit.mot.com/1257205
Reviewed-by: Xiaojun Ji <jixj@motorola.com>
Reviewed-by: Huosheng Liao <liaohs@motorola.com>
Reviewed-on: https://gerrit.mot.com/1338832
Reviewed-on: https://gerrit.mot.com/1449034
Reviewed-on: https://gerrit.mot.com/1511634
Reviewed-by: Zonghua Liu <a17671@motorola.com>
Reviewed-by: Wang Wang <wangwang1@lenovo.com>

drivers/usb/gadget/configfs.c

@@ -1358,7 +1358,8 @@ static int configfs_composite_bind(struct usb_gadget *gadget,
 		cdev->use_os_string = true;
 		cdev->b_vendor_code = gi->b_vendor_code;
 		memcpy(cdev->qw_sign, gi->qw_sign, OS_STRING_QW_SIGN_LEN);
-	}
+	} else
+		cdev->use_os_string = false;
 
 	if (gadget_is_otg(gadget) && !otg_desc[0]) {
 		struct usb_descriptor_header *usb_desc;