block: add blk_queue_fua() helper function

So we can check FUA support status from the iomap direct IO code.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

include/linux/blkdev.h

@@ -737,6 +737,7 @@ bool blk_queue_flag_test_and_clear(unsigned int flag, struct request_queue *q);
 #define blk_queue_quiesced(q)	test_bit(QUEUE_FLAG_QUIESCED, &(q)->queue_flags)
 #define blk_queue_preempt_only(q)				\
 	test_bit(QUEUE_FLAG_PREEMPT_ONLY, &(q)->queue_flags)
+#define blk_queue_fua(q)	test_bit(QUEUE_FLAG_FUA, &(q)->queue_flags)
 
 extern int blk_set_preempt_only(struct request_queue *q);
 extern void blk_clear_preempt_only(struct request_queue *q);