hw/vfio/pci: fix vfio_pci_hot_reset_result trace point

"%m" format specifier is not interpreted by the trace infrastructure
and thus "%m" is output instead of the actual errno string. Fix it by
outputting strerror(errno).

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20220502094223.36384-2-yi.l.liu@intel.com
[aw: replace commit log as provided by Eric]
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

hw/vfio/pci.c

@@ -2380,7 +2380,7 @@ static int vfio_pci_hot_reset(VFIOPCIDevice *vdev, bool single)
     g_free(reset);
 
     trace_vfio_pci_hot_reset_result(vdev->vbasedev.name,
-                                    ret ? "%m" : "Success");
+                                    ret ? strerror(errno) : "Success");
 
 out:
     /* Re-enable INTx on affected devices */