block: sanitize blk_get_request calling conventions

Switch everyone to blk_get_request_flags, and then rename
blk_get_request_flags to blk_get_request.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/scsi/osd/osd_initiator.c

@@ -1570,7 +1570,7 @@ static struct request *_make_request(struct request_queue *q, bool has_write,
 	int ret;
 
 	req = blk_get_request(q, has_write ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN,
-			GFP_KERNEL);
+			0);
 	if (IS_ERR(req))
 		return req;