[SCSI] dec_esp: Remove driver

This driver depends on the deprecated NCR53C9X core and needs to be converted
to the esp_scsi core.

Acked-by: Boaz Harrosh <bharrosh@panasas.com>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>