USB: remove unnecessary tests in isp116x and sl811

This patch (as962) cleans up some code I forgot to remove earlier in
the isp116x and sl811 HCDs.  There is no longer any need to check for
unlink-during-submit; it can't happen since the endpoint queues are
now under the protection of the HCD-private spinlock.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: David Brownell <david-b@pacbell.net>
CC: Olav Kongas <ok@artecdesign.ee>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>