Add kernel 5.15 for RPI4 support

root/target/linux/bcm27xx/patches-5.15/0468-dwc_otg-Update-NetBSD-usb.h-header-licence.patch

@@ -0,0 +1,38 @@
+From 6f1e491841b9aefe338491f9da0a4afc40bf09ef Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.com>
+Date: Mon, 5 Jul 2021 19:38:21 +0100
+Subject: [PATCH 468/634] dwc_otg: Update NetBSD usb.h header licence
+
+NetBSD have changed their licensing requirements such that the 2-clause
+licence is preferred. Update usb.h in the downstream dwc_otg code
+accordingly.
+
+See https://www.netbsd.org/about/redistribution.html for more
+information.
+
+Signed-off-by: Phil Elwell <phil@raspberrypi.com>
+---
+ drivers/usb/host/dwc_common_port/usb.h | 7 -------
+ 1 file changed, 7 deletions(-)
+
+diff --git a/drivers/usb/host/dwc_common_port/usb.h b/drivers/usb/host/dwc_common_port/usb.h
+index f78593575736..b1cedb1876b7 100644
+--- a/drivers/usb/host/dwc_common_port/usb.h
++++ b/drivers/usb/host/dwc_common_port/usb.h
+@@ -14,13 +14,6 @@
+  * 2. Redistributions in binary form must reproduce the above copyright
+  *    notice, this list of conditions and the following disclaimer in the
+  *    documentation and/or other materials provided with the distribution.
+- * 3. All advertising materials mentioning features or use of this software
+- *    must display the following acknowledgement:
+- *        This product includes software developed by the NetBSD
+- *        Foundation, Inc. and its contributors.
+- * 4. Neither the name of The NetBSD Foundation nor the names of its
+- *    contributors may be used to endorse or promote products derived
+- *    from this software without specific prior written permission.
+  *
+  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+-- 
+2.33.1
+