These operations are supported on AST2600 series of machines.

Signed-off-by: Klaus Heinrich Kiwi <klaus@linux.vnet.ibm.com>

---
Changes since V2:
 * Fixed spurious comment removing conditional 

Changes since V1:

 * Use address_space_ldl_le() to load single addresses instead of
   address_space_map()
 * Updated documentation
 * Removed several uneeded variables / casts
 * Confirmed behavior on real hardware for register masks, IRQ register
   etc
 * Adjusted testcases accordingly
 * Coding style fixes

 docs/system/arm/aspeed.rst     |   2 +-
 hw/misc/aspeed_hace.c          | 126 +++++++++++++++++++++++++++++++--
 tests/qtest/aspeed_hace-test.c | 156 ++++++++++++++++++++++++++++++++++++++---
 3 files changed, 268 insertions(+), 16 deletions(-)