USB: ipaq: fix oops when device is plugged in

This patch (as1293) fixes a problem with the ipaq serial driver.  It
tries to bind to all the interfaces, even those that don't have enough
endpoints.  The symptom is an invalid memory reference and oops when
the device is plugged in.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: stable <stable@kernel.org>
Tested-by: Matthias Geissert <geissert@mathematik.tu-darmstadt.de>
Tested-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>