lib: Add rp2040 build files

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

lib/rp2040/hardware/structs/syscfg.h

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef _HARDWARE_STRUCTS_SYSCFG_H
+#define _HARDWARE_STRUCTS_SYSCFG_H
+
+#include "hardware/address_mapped.h"
+#include "hardware/platform_defs.h"
+#include "hardware/regs/syscfg.h"
+
+typedef struct {
+    io_rw_32 proc0_nmi_mask;
+    io_rw_32 proc1_nmi_mask;
+    io_rw_32 proc_config;
+    io_rw_32 proc_in_sync_bypass;
+    io_rw_32 proc_in_sync_bypass_hi;
+    io_rw_32 dbgforce;
+    io_rw_32 mempowerdown;
+} syscfg_hw_t;
+
+#define syscfg_hw ((syscfg_hw_t *const)SYSCFG_BASE)
+
+#endif