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/family.mk

@@ -0,0 +1,43 @@
+MCU_DIR = hw/mcu/broadcom
+DEPS_SUBMODULES += $(MCU_DIR)
+
+include $(TOP)/$(BOARD_PATH)/board.mk
+
+CFLAGS += \
+	-Wall \
+	-O0 \
+	-ffreestanding \
+	-nostdlib \
+	-nostartfiles \
+	-mgeneral-regs-only \
+	-std=c17
+
+# mcu driver cause following warnings
+CFLAGS += -Wno-error=cast-qual
+
+SRC_C += \
+	src/portable/synopsys/dwc2/dcd_dwc2.c \
+	$(MCU_DIR)/broadcom/gen/interrupt_handlers.c \
+	$(MCU_DIR)/broadcom/gpio.c \
+	$(MCU_DIR)/broadcom/interrupts.c \
+	$(MCU_DIR)/broadcom/mmu.c \
+	$(MCU_DIR)/broadcom/caches.c \
+	$(MCU_DIR)/broadcom/vcmailbox.c
+
+SKIP_NANOLIB = 1
+
+LD_FILE = $(MCU_DIR)/broadcom/link$(SUFFIX).ld
+
+INC += \
+	$(TOP)/$(BOARD_PATH) \
+	$(TOP)/$(MCU_DIR)
+
+SRC_S += $(MCU_DIR)/broadcom/boot$(SUFFIX).S
+
+$(BUILD)/kernel$(SUFFIX).img: $(BUILD)/$(PROJECT).elf
+	$(OBJCOPY) -O binary $^ $@
+
+# Copy to kernel to netboot drive or SD card
+# Change destinaation to fit your need
+flash: $(BUILD)/kernel$(SUFFIX).img
+	@$(CP) $< /home/$(USER)/Documents/code/pi_tinyusb/boot_cpy