firewire: ohci: consolidate context status flags

"firewire: ohci: restart iso DMA contexts on resume from low power mode"
added the flag struct context.active and "firewire: ohci: cache the
context run bit" added struct context.running.

These flags contain the same information; combine them.
Also, normalize whitespace in pci_resume().

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>