libata: give devices one last chance even if recovery failed with -EINVAL

After certain errors, some devices report complete garbage on
IDENTIFY.  This can cause ata_dev_read_id() to fail with -EINVAL
resulting in immediate disabling of the device.  Give the device one
last chance after -EINVAL to allow recovery from such situations.  As
-EINVAL is triggered very rarely, this shouldn't cause any noticeable
affect on more common error paths.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Harald Dunkel <harald.dunkel@t-online.de>
Signed-off-by: Jeff Garzik <jeff@garzik.org>