wifi: ath9k: use unmanaged PCI functions in ath9k_pci_owl_loader

Only managed PCI resource in the driver is the iomapped bar. However the bar
is unmapped in the same function. Therefore using the device-managed
versions just causes overhead, w/o any benefit. Once this is switched to the
non-managed versions, there's nothing left to be managed for
pcim_enable_device(). Therefore we can reduce overhead here too and switch to
the non-managed version as well. This includes removing the no longer needed
call to pcim_pin_device().

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://patch.msgid.link/3b46f6c7-4372-4cc9-9a7c-2c1c06d29324@gmail.com