ata: libata: add reset tracepoints

To follow the flow of control we should be using tracepoints, as
they will tie in with the actual I/O flow and deliver a better
overview about what it happening.
This patch adds tracepoints for hard reset, soft reset, and postreset
and adds them in the libata-eh control flow.
With that we can drop the reset DPRINTK calls in the various drivers.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>