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)

src/tusb_option.h

@@ -132,6 +132,8 @@
 
 // Broadcom
 #define OPT_MCU_BCM2711          1700 ///< Broadcom BCM2711
+#define OPT_MCU_BCM2835          1701 ///< Broadcom BCM2835
+#define OPT_MCU_BCM2837          1702 ///< Broadcom BCM2837
 
 // Infineon
 #define OPT_MCU_XMC4000          1800 ///< Infineon XMC4000