[SCSI] pci2000: Delete unused header file.

This driver was removed a while ago by commit

099175c9

However, it seems that pci2000.h wasn't properly eliminated, so remove
it now.

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>