ublk: support UBLK_F_INTEGRITY

Now that all the components of the ublk integrity feature have been
implemented, add UBLK_F_INTEGRITY to UBLK_F_ALL, conditional on block
layer integrity support (CONFIG_BLK_DEV_INTEGRITY). This allows ublk
servers to create ublk devices with UBLK_F_INTEGRITY set and
UBLK_U_CMD_GET_FEATURES to report the feature as supported.

Signed-off-by: Stanley Zhang <stazhang@purestorage.com>
[csander: make feature conditional on CONFIG_BLK_DEV_INTEGRITY]
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Stanley Zhang

drivers/block/ublk_drv.c

@@ -75,7 +75,8 @@
 		| UBLK_F_AUTO_BUF_REG \
 		| UBLK_F_QUIESCE \
 		| UBLK_F_PER_IO_DAEMON \
-		| UBLK_F_BUF_REG_OFF_DAEMON)
+		| UBLK_F_BUF_REG_OFF_DAEMON \
+		| (IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY) ? UBLK_F_INTEGRITY : 0))
 
 #define UBLK_F_ALL_RECOVERY_FLAGS (UBLK_F_USER_RECOVERY \
 		| UBLK_F_USER_RECOVERY_REISSUE \