[SCSI] esp_scsi: remove __dev{init,exit}

Since scsi_esp_{,un}register() are EXPORT_SYMBOL'ed, these functions
(and the functions they use) can't be __dev{init,exit}.

Based on a bug report by Rob Landley.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>