commit 6d8ca28f upstream.

Currently, ata_sff_softreset is skipped for controllers with no ctl port.
But that also skips ata_sff_dev_classify required for device detection.
This means that libata is currently broken on controllers with no ctl port.

No device connected:
[    1.872480] pata_isapnp 01:01.02: activated
[    1.889823] scsi2 : pata_isapnp
[    1.890109] ata3: PATA max PIO0 cmd 0x1e8 ctl 0x0 irq 11
[    6.888110] ata3.01: qc timeout (cmd 0xec)
[    6.888179] ata3.01: failed to IDENTIFY (I/O error, err_mask=0x5)
[   16.888085] ata3.01: qc timeout (cmd 0xec)
[   16.888147] ata3.01: failed to IDENTIFY (I/O error, err_mask=0x5)
[   46.888086] ata3.01: qc timeout (cmd 0xec)
[   46.888148] ata3.01: failed to IDENTIFY (I/O error, err_mask=0x5)
[   51.888100] ata3.00: qc timeout (cmd 0xec)
[   51.888160] ata3.00: failed to IDENTIFY (I/O error, err_mask=0x5)
[   61.888079] ata3.00: qc timeout (cmd 0xec)
[   61.888141] ata3.00: failed to IDENTIFY (I/O error, err_mask=0x5)
[   91.888089] ata3.00: qc timeout (cmd 0xec)
[   91.888152] ata3.00: failed to IDENTIFY (I/O error, err_mask=0x5)

ATAPI device connected:
[    1.882061] pata_isapnp 01:01.02: activated
[    1.893430] scsi2 : pata_isapnp
[    1.893719] ata3: PATA max PIO0 cmd 0x1e8 ctl 0x0 irq 11
[    6.892107] ata3.01: qc timeout (cmd 0xec)
[    6.892171] ata3.01: failed to IDENTIFY (I/O error, err_mask=0x5)
[   16.892079] ata3.01: qc timeout (cmd 0xec)
[   16.892138] ata3.01: failed to IDENTIFY (I/O error, err_mask=0x5)
[   46.892079] ata3.01: qc timeout (cmd 0xec)
[   46.892138] ata3.01: failed to IDENTIFY (I/O error, err_mask=0x5)
[   46.908586] ata3.00: ATAPI: ACER CD-767E/O, V1.5X, max PIO2, CDB intr
[   46.924570] ata3.00: configured for PIO0 (device error ignored)
[   46.926295] scsi 2:0:0:0: CD-ROM            ACER     CD-767E/O        1.5X PQ: 0 ANSI: 5
[   46.984519] sr0: scsi3-mmc drive: 6x/6x xa/form2 tray
[   46.984592] cdrom: Uniform CD-ROM driver Revision: 3.20

So don't skip ata_sff_softreset, just skip the reset part of ata_bus_softreset
if the ctl port is not available.

This makes IDE port on ES968 behave correctly:

No device connected:
[    4.670888] pata_isapnp 01:01.02: activated
[    4.673207] scsi host2: pata_isapnp
[    4.673675] ata3: PATA max PIO0 cmd 0x1e8 ctl 0x0 irq 11
[    7.081840] Adding 2541652k swap on /dev/sda2.  Priority:-1 extents:1 across:2541652k

ATAPI device connected:
[    4.704362] pata_isapnp 01:01.02: activated
[    4.706620] scsi host2: pata_isapnp
[    4.706877] ata3: PATA max PIO0 cmd 0x1e8 ctl 0x0 irq 11
[    4.872782] ata3.00: ATAPI: ACER CD-767E/O, V1.5X, max PIO2, CDB intr
[    4.888673] ata3.00: configured for PIO0 (device error ignored)
[    4.893984] scsi 2:0:0:0: CD-ROM            ACER     CD-767E/O        1.5X PQ: 0 ANSI: 5
[    7.015578] Adding 2541652k swap on /dev/sda2.  Priority:-1 extents:1 across:2541652k
Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>