libata: move reset freeze/thaw handling into ata_eh_reset()

Previously reset freeze/thaw handling lived outside of ata_eh_reset()
mainly because the original PMP reset code needed the port frozen
while resetting all the fan-out ports, which is no longer the case.

This patch moves freeze/thaw handling into ata_eh_reset().
@prereset() and @postreset() are now called w/o freezing the port
although @prereset() an be called frozen if the port is frozen prior
to entering ata_eh_reset().

This makes code simpler and will help removing hotplug event related
races.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/ata/libata-pmp.c

@@ -700,8 +700,6 @@ static int sata_pmp_eh_recover_pmp(struct ata_port *ap,
 	if (ehc->i.action & ATA_EH_RESET) {
 		struct ata_link *tlink;
 
-		ata_eh_freeze_port(ap);
-
 		/* reset */
 		rc = ata_eh_reset(link, 0, prereset, softreset, hardreset,
 				  postreset);
@@ -711,8 +709,6 @@ static int sata_pmp_eh_recover_pmp(struct ata_port *ap,
 			goto fail;
 		}
 
-		ata_eh_thaw_port(ap);
-
 		/* PMP is reset, SErrors cannot be trusted, scan all */
 		ata_port_for_each_link(tlink, ap) {
 			struct ata_eh_context *ehc = &tlink->eh_context;