subsys: usb: host: do enhancement for class register.

1. check class_list empty for class register.
2. cleanup the code for usbh_class_is_matching

Signed-off-by: Aiden Hu <[email protected]>

Author: AidenHu

subsys/usb/host/usbh_class.c

@@ -21,11 +21,17 @@ int usbh_register_all_classes(struct usbh_context *uhs_ctx)
 		struct usbh_class_data *cdata_registered;
 		bool already_registered = false;
 
+		if (cdata_existing == NULL) {
+			continue;
+		}
+
 		/* Check if already registered */
-		SYS_SLIST_FOR_EACH_CONTAINER(&uhs_ctx->class_list, cdata_registered, node) {
-			if (cdata_existing == cdata_registered) {
-				already_registered = true;
-				break;
+		if (!sys_slist_is_empty(&uhs_ctx->class_list)) {
+			SYS_SLIST_FOR_EACH_CONTAINER(&uhs_ctx->class_list, cdata_registered, node) {
+				if (cdata_existing == cdata_registered) {
+					already_registered = true;
+					break;
+				}
 			}
 		}
 
@@ -65,16 +71,9 @@ bool usbh_class_is_matching(struct usbh_class_data *cdata,
 	for (int i = 0; cdata->filters[i].flags != 0; i++) {
 		const struct usbh_class_filter *filter = &cdata->filters[i];
 
-		if (filter->flags & USBH_CLASS_FILTER_VID) {
-			if (filter->vid != device_info->vid) {
-				continue;
-			}
-		}
-
-		if (filter->flags & USBH_CLASS_FILTER_VID) {
-			if (filter->vid == device_info->vid) {
-				continue;
-			}
+		if ((filter->flags & USBH_CLASS_FILTER_VID) && 
+			(filter->vid != device_info->vid)) {
+			continue;
 		}
 
 		if (filter->flags & USBH_CLASS_FILTER_CODE_TRIPLE) {