convert busId to int8 instead of uint8

The PciInfo struct has been updated to use int8 for
BusId as opposed to uint8 as part of the sync of
go-nvml with CUDA 13.1

Signed-off-by: Tariq Ibrahim <tibrahim@nvidia.com>

Author: tariq1890

pkg/nvlib/device/device_test.go

@@ -28,7 +28,7 @@ import (
 func pciInfoWithBusID(busID string) nvml.PciInfo {
 	var info nvml.PciInfo
 	for i := 0; i < len(busID) && i < len(info.BusId); i++ {
-		info.BusId[i] = uint8(busID[i])
+		info.BusId[i] = int8(busID[i])
 	}
 	return info
 }