eata: remove driver_lock

port_detect is only called from the module_init routine and thus implicitly
serialized, so remove the driver lock which was held over potentially
sleeping function calls.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Arthur Marsh <arthur.marsh@internode.on.net>
Tested-by: Arthur Marsh <arthur.marsh@internode.on.net>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>