Bugfix: Use only one PTD for one endpoint

Original isp116x-hcd code prepared multiple PTDs for longer than 16
byte transfers for one endpoint. That is unnecessary because the
ISP116x is able to split long data from one PTD into multiple
transactions based on the buffer size of the endpoint. It also caused
serious problems if the endpoint NAKed some of the transactions. In
that case ISP116x wouldn't notice that the other PTDs were for the same
endpoint and would try the other PTDs possibly out of order. That would
break the whole transfer.

This patch makes isp116x_submit_job to use one PTD for one transfer.

Signed-off-by: Timo Ketola <timo.ketola@exertus.fi>
Signed-off-by: Markus Klotzbuecher <mk@denx.de>