tgt: remove SCSI_TGT and SCSI_FC_TGT_ATTRS

The Kconfig symbols SCSI_TGT and SCSI_FC_TGT_ATTRS are unused since
"tgt: removal". Setting them has no effect. Remove these symbols.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Christoph Hellwig <hch@lst.de>