block: unexport DISK_EVENT_MEDIA_CHANGE for legacy/fringe drivers

In-kernel disk event polling doesn't matter for legacy/fringe drivers
and may lead to infinite event loop if ->check_events() implementation
generates events on level condition instead of edge.

Now that block layer supports suppressing exporting unlisted events,
simply leaving disk->events cleared allows these drivers to keep the
internal revalidation behavior intact while avoiding weird
interactions with userland event handler.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

drivers/block/paride/pcd.c

@@ -320,7 +320,6 @@ static void pcd_init_units(void)
 		disk->first_minor = unit;
 		strcpy(disk->disk_name, cd->name);	/* umm... */
 		disk->fops = &pcd_bdops;
-		disk->events = DISK_EVENT_MEDIA_CHANGE;
 	}
 }
 

drivers/block/paride/pd.c

@@ -837,7 +837,6 @@ static void pd_probe_drive(struct pd_unit *disk)
 	p->fops = &pd_fops;
 	p->major = major;
 	p->first_minor = (disk - pd) << PD_BITS;
-	p->events = DISK_EVENT_MEDIA_CHANGE;
 	disk->gd = p;
 	p->private_data = disk;
 	p->queue = pd_queue;

drivers/block/paride/pf.c

@@ -294,7 +294,6 @@ static void __init pf_init_units(void)
 		disk->first_minor = unit;
 		strcpy(disk->disk_name, pf->name);
 		disk->fops = &pf_fops;
-		disk->events = DISK_EVENT_MEDIA_CHANGE;
 		if (!(*drives[unit])[D_PRT])
 			pf_drive_count++;
 	}