firewire: ohci: use generic power management

firewire: ohci: use generic power management

Drivers using legacy PM have to manage PCI states and device's PM states
themselves. They also need to take care of configuration registers.

With improved and powerful support of generic PM, PCI Core takes care of
above mentioned, device-independent, jobs.

This driver makes use of PCI helper functions like
pci_save/restore_state(), pci_disable_device() and pci_set_power_state() to
do required operations. In generic mode, they are no longer needed.

Change function parameter in both .suspend() and .resume() to
"struct device*" type. Use to_pci_dev() to get "struct pci_dev*" variable.

Compile-tested only.

Maintainer has tested the changes on non-PowerPC platform and got no
failure of the suspend/resume operations.

Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
Link: https://lore.kernel.org/r/20200720150715.624520-1-vaibhavgupta40@gmail.com
Tested-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by; Takashi Sakamoto <o-takashi@sakamocchi.jp<