coresight: abort tracing for unhandled aborts

Add trace event to abort tracing for unhandled aborts such as
data abort and prefetch abort. A common event 'trace_unhandled_abort'
is shared for all unhandled aborts.

Change-Id: I6da9b30c74be48252402188a6f9a7703d21d6276
Signed-off-by: Sarang Joshi <spjoshi@codeaurora.org>