hw/vfio/pci: fix vfio_pci_hot_reset_result trace point

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>