arm: Move M-profile RAS register block into its own device

Currently we implement the RAS register block within the NVIC device.
It isn't really very tightly coupled with the NVIC proper, so instead
move it out into a sysbus device of its own and have the top level
ARMv7M container create it and map it into memory at the right
address.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alexandre Iooss <erdnaxe@crans.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Luc Michel <luc@lmichel.fr>
Reviewed-by: Damien Hedde <damien.hedde@greensocs.com>
Message-id: 20210812093356.1946-2-peter.maydell@linaro.org

include/hw/misc/armv7m_ras.h

@@ -0,0 +1,37 @@
+/*
+ * Arm M-profile RAS (Reliability, Availability and Serviceability) block
+ *
+ * Copyright (c) 2021 Linaro Limited
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 or
+ *  (at your option) any later version.
+ */
+
+/*
+ * This is a model of the RAS register block of an M-profile CPU
+ * (the registers starting at 0xE0005000 with ERRFRn).
+ *
+ * QEMU interface:
+ *  + sysbus MMIO region 0: the register bank
+ *
+ * The QEMU implementation currently provides "minimal RAS" only.
+ */
+
+#ifndef HW_MISC_ARMV7M_RAS_H
+#define HW_MISC_ARMV7M_RAS_H
+
+#include "hw/sysbus.h"
+
+#define TYPE_ARMV7M_RAS "armv7m-ras"
+OBJECT_DECLARE_SIMPLE_TYPE(ARMv7MRAS, ARMV7M_RAS)
+
+struct ARMv7MRAS {
+    /*< private >*/
+    SysBusDevice parent_obj;
+
+    /*< public >*/
+    MemoryRegion iomem;
+};
+
+#endif