firewire: ohci: obsolete usage of deprecated API for MSI

The usage of the pair of pci_enable_msi() and pci_disable_msi() is
deprecated.

This commit uses the preferred pair of API for the purpose. The call of
pci_alloc_irq_vectors() can have a subeffect to change the return value
of pci_dev_msi_enabled().

Link: https://lore.kernel.org/r/20240331135037.191479-4-o-takashi@sakamocchi.jp


Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>