When EH gives up after repeated exceptions, it doesn't't clear the
PENDING bit on exit which leaves PENDING bit set without EH actually
scheduled.  This makes ata_port_wait_eh() to wait forever makes rmmod
hang on such port.  Fix it by clearing the flag.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>