usb/ohci: Don't use packet from OHCIState for isochronous transfers

usb/ohci: Don't use packet from OHCIState for isochronous transfers

Since isochronous transfers cannot be handled async (the function
returns error in that case) we don't need to remember the packet.
Avoid using the usb_packet field in OHCIState (as that can be a
waiting async packet on another endpoint) and allocate and use a local
USBPacket for the iso transfer instead. After this we don't have to
care if we're called from a completion callback or not so we can drop
that parameter as well.

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Message-Id: <bf523d40f8088a84383cb00ffd2e6e82fa47790d.1643117600.git.balaton@eik.bme.hu>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>