firewire: ohci: optimize iso context checks in the interrupt handler

When the isochRx/isochTx bit is clear, we do not need to read the
corresponding iso interrupt event register.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
1 file changed