Add Raspberry Pi Zero W and Zero 2 W

These are different Broadcom chips. The peripherals are essentially
the same. The main differences are:
* The CPU(s)
* The interrupt controller
* The peripheral base address (but not the peripherals that we use)

hw/bsp/bcm2835/boards/raspberrypi_cm4/board.h

@@ -0,0 +1,38 @@
+/* 
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020, Ha Thach (tinyusb.org)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * This file is part of the TinyUSB stack.
+ */
+
+#ifndef BOARD_H_
+#define BOARD_H_
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+#ifdef __cplusplus
+ }
+#endif
+
+#endif /* BOARD_H_ */

hw/bsp/bcm2835/boards/raspberrypi_cm4/board.mk

@@ -0,0 +1,9 @@
+CFLAGS += -mcpu=cortex-a72 \
+          -DBCM_VERSION=2711 \
+          -DCFG_TUSB_MCU=OPT_MCU_BCM2711
+
+CROSS_COMPILE = aarch64-none-elf-
+
+SUFFIX = 8
+
+INC += $(TOP)/lib/CMSIS_5/CMSIS/Core_A/Include