qtest/libqos/pci: Do not write to PBA memory

The PCI Local Bus Specification says the result of writes to MSI-X
PBA memory is undefined. QEMU implements them as no-ops, so remove
the pointless write from qpci_msix_pending().

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Message-Id: <20250117172244.406206-2-npiggin@gmail.com>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

tests/qtest/libqos/pci.c

@@ -328,8 +328,6 @@ bool qpci_msix_pending(QPCIDevice *dev, uint16_t entry)
 
     g_assert(dev->msix_enabled);
     pba_entry = qpci_io_readl(dev, dev->msix_pba_bar, dev->msix_pba_off + off);
-    qpci_io_writel(dev, dev->msix_pba_bar, dev->msix_pba_off + off,
-                   pba_entry & ~(1 << bit_n));
     return (pba_entry & (1 << bit_n)) != 0;
 }