[SCSI] SCSI: aic7xxx_osm_pci resource leak fix.

Fix resource leak in
drivers/scsi/aic7xxx/aic7xxx_osm_pci.c::ahc_linux_pci_dev_probe()

Found by the coverity checker (#668)

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>