aerdrv: Enhanced AER logging

This patch will provide a more reliable and easy way for user-space
applications to have access to AER logs rather than reading them from the
message buffer. It also provides a way to notify user-space when an AER
event occurs.

The aer driver is updated to generate a trace event of function 'aer_event'
when a PCIe error is reported over the AER interface.  The trace event was
added to both the interrupt based aer path and the firmware first path.

Signed-off-by: Lance Ortiz <lance.ortiz@hp.com>
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: Boris Petkov <bp@alien8.de>
Signed-off-by: Tony Luck <tony.luck@intel.com>