roms: Add virtual Boot ROM for NPCM7xx SoCs

This is a minimalistic boot ROM written specifically for use with QEMU.
It supports loading the second-stage loader from SPI flash into RAM, SMP
boot, and not much else.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Havard Skinnemoen <hskinnemoen@google.com>
Message-id: 20200911052101.2602693-7-hskinnemoen@google.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

pc-bios/README

@@ -71,3 +71,9 @@
   ("Simplified BSD License" or "FreeBSD License", SPDX: BSD-2-Clause). OpenSBI
   source code also contains code reused from other projects desribed here:
   https://github.com/riscv/opensbi/blob/master/ThirdPartyNotices.md.
+
+- npcm7xx_bootrom.bin is a simplified, free (Apache 2.0) boot ROM for Nuvoton
+  NPCM7xx BMC devices. It currently implements the bare minimum to load, parse,
+  initialize and run boot images stored in SPI flash, but may grow more
+  features over time as needed. The source code is available at:
+  https://github.com/google/vbootrom

pc-bios/meson.build

@@ -81,6 +81,7 @@ blobs = files(
   'opensbi-riscv64-generic-fw_dynamic.bin',
   'opensbi-riscv32-generic-fw_dynamic.elf',
   'opensbi-riscv64-generic-fw_dynamic.elf',
+  'npcm7xx_bootrom.bin',
 )
 
 if install_blobs