target: Add Third Party Copy (3PC) bit in INQUIRY response

target: Add Third Party Copy (3PC) bit in INQUIRY response

This patch adds the Third Party Copy (3PC) bit to signal support
for EXTENDED_COPY within standard inquiry response data.

Also add emulate_3pc device attribute in configfs (enabled by default)
to allow the exposure of this bit to be disabled, if necessary.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Zach Brown <zab@redhat.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>