target/spc: Add protection related bits to INQUIRY EVPD=0x86

This patch updates spc_emulate_evpd_86() (extended INQUIRY) to
report GRD_CHK (Guard Check) and REF_CHK (Reference Check) bits
when DIF emulation is enabled by the backend device.

Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>