hw/arm/mps2: New board model mps2-an500

Implement a model of the MPS2 with the AN500 firmware. This is
similar to the AN385, with the following differences:
 * Cortex-M7 CPU
 * PSRAM is at 0x6000_0000
 * Ethernet is at 0xa000_0000
 * No zbt_boot_ctrl remapping of the low 16K
   (but QEMU doesn't implement this anyway)
 * no "block RAM" at 0x01000000

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20200903202048.15370-3-peter.maydell@linaro.org
diff --git a/docs/system/arm/mps2.rst b/docs/system/arm/mps2.rst
index e680a4c..7f2e9c8 100644
--- a/docs/system/arm/mps2.rst
+++ b/docs/system/arm/mps2.rst
@@ -1,5 +1,5 @@
-Arm MPS2 boards (``mps2-an385``, ``mps2-an386``, ``mps2-an505``, ``mps2-an511``, ``mps2-an521``)
-================================================================================================
+Arm MPS2 boards (``mps2-an385``, ``mps2-an386``, ``mps2-an500``, ``mps2-an505``, ``mps2-an511``, ``mps2-an521``)
+================================================================================================================
 
 These board models all use Arm M-profile CPUs.
 
@@ -14,6 +14,8 @@
   Cortex-M3 as documented in ARM Application Note AN385
 ``mps2-an386``
   Cortex-M4 as documented in ARM Application Note AN386
+``mps2-an500``
+  Cortex-M7 as documented in ARM Application Note AN500
 ``mps2-an511``
   Cortex-M3 'DesignStart' as documented in AN511
 ``mps2-an505``