[SCSI] ESP: Increase ESP_BUS_TIMEOUT to 275.

This matches the original driver's value and seems to be
necessary for some disks on sun4c systems.

Reported by Mark Fortescue <mark@mtfhpc.demon.co.uk>

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>