proc_bus_pci_ioctl: remove pointless BKL usage

The BKL was pushed into this function when it was converted to use the
unlocked_ioctl interface, but nothing that the function touches is
actually protected by the BKL.  So just remove the BKL entirely, so that
we finally can get a realistic system build without the BKL being
enabled at all.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>