vfio: selftests: Prefix logs with device BDF where relevant

vfio: selftests: Prefix logs with device BDF where relevant

Prefix log messages with the device's BDF where relevant. This will help
understanding VFIO selftests logs when tests are run with multiple
devices.

Reviewed-by: Alex Mastro <amastro@fb.com>
Tested-by: Alex Mastro <amastro@fb.com>
Reviewed-by: Raghavendra Rao Ananta <rananta@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20251126231733.3302983-9-dmatlack@google.com
Signed-off-by: Alex Williamson <alex@shazbot.org>