PCI AER: software error injection

Debugging PCIE AER code can be very difficult because it is hard
to trigger various real hardware errors. This patch provide a
software based error injection tool, which can fake various PCIE
errors with a user space helper tool named "aer-inject". Which
can be gotten from:

  http://www.kernel.org/pub/linux/kernel/people/yhuang/

The patch fakes AER error by faking some PCIE AER related
registers and an AER interrupt for specified the PCIE device.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>