tracing: add trace event for memory-failure

tracing: add trace event for memory-failure

RAS user space tools like rasdaemon which base on trace event, could
receive mce error event, but no memory recovery result event.  So, I want
to add this event to make this scenario complete.

This patch add a event at ras group for memory-failure.

The output like below:
#  tracer: nop
#
#  entries-in-buffer/entries-written: 2/2   #P:24
#
#                               _-----=> irqs-off
#                              / _----=> need-resched
#                             | / _---=> hardirq/softirq
#                             || / _--=> preempt-depth
#                             ||| /     delay
#            TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
#               | |       |   ||||       |         |
       mce-inject-13150 [001] ....   277.019359: memory_failure_event: pfn 0x19869: recovery action for free buddy page: Delayed

[[email protected]: fix build error]
Signed-off-by: Xie XiuQi <[email protected]>
Reviewed-by: Naoya Horiguchi <[email protected]>
Acked-by: Steven Rostedt <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Chen Gong <[email protected]>
Cc: Jim Davis <[email protected]>
Signed-off-by: Xie XiuQi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>