switchtec: Add IOCTLs to the Switchtec driver

Add a couple of special IOCTLs to:

* Inform userspace of firmware partition locations
* Pass event counts and allow userspace to wait on events
* Translate PFF numbers used by the switch to port numbers

[Dan Carpenter <dan.carpenter@oracle.com>: fix off-by-one in
ioctl_event_ctl()]
Tested-by: Krishna Dhulipala <krishnad@fb.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Stephen Bates <stephen.bates@microsemi.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Wei Zhang <wzhang@fb.com>
Reviewed-by: Jens Axboe <axboe@fb.com>

Documentation/ioctl/ioctl-number.txt

@@ -191,6 +191,7 @@ Code  Seq#(hex)	Include File		Comments
 'W'	00-1F	linux/watchdog.h	conflict!
 'W'	00-1F	linux/wanrouter.h	conflict!		(pre 3.9)
 'W'	00-3F	sound/asound.h		conflict!
+'W'	40-5F   drivers/pci/switch/switchtec.c
 'X'	all	fs/xfs/xfs_fs.h		conflict!
 		and fs/xfs/linux-2.6/xfs_ioctl32.h
 		and include/linux/falloc.h