Simplify device discovery using go-nvlib and add NVSwitch support

[zvonkok]

• Replace manual PCI device enumeration with go-nvlib/nvpci library
• Add support for discovering NVSwitches bound to vfio-pci driver
• NVSwitches always use their actual device name (ignore PGPUAlias)
• Remove redundant helper functions (readIDFromFileFunc, readLinkFunc, getDeviceName, locateVendor, readVFIODev)
• Simplify Allocate() by using stored IommuFD instead of re-reading sysfs
• Remove unused constants (basePath, pciIdsFilePath)
• Fix context leak in grpc connect()
• Update tests to use nvpci.InterfaceMock

[Copilot]

Pull request overview

This PR simplifies device discovery by replacing manual PCI enumeration with the go-nvlib/nvpci library and adds support for discovering NVSwitches. The refactoring removes redundant helper functions, fixes a context leak in gRPC connection, and updates tests to use mocks.

Changes:

• Replaced manual PCI device enumeration with go-nvlib/nvpci library
• Added NVSwitch device discovery support (with special handling to ignore PGPUAlias)
• Fixed context leak in grpc connect() function by properly deferring cancel
• Removed unused constants and redundant helper functions
• Updated tests to use nvpci.InterfaceMock

Reviewed changes

Copilot reviewed 6 out of 44 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
pkg/device_plugin/device_plugin.go	Core refactoring using go-nvlib for device discovery and NVSwitch support
pkg/device_plugin/generic_device_plugin.go	Fixed context leak in connect() and simplified Allocate()
pkg/device_plugin/constants.go	Removed unused constants (basePath, pciIdsFilePath)
pkg/device_plugin/device_plugin_test.go	Refactored tests to use nvpci.InterfaceMock
pkg/device_plugin/generic_device_plugin_test.go	Updated test data structures and improved test cases
go.mod	Added go-nvlib dependency and updated Go version to 1.25
vendor/modules.txt	Added golangci-lint and moq dependencies
vendor/k8s.io/klog/v2/*	Removed klog/v2 dependency

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[rajatchopra]

LGTM
Will test to verify if two device plugin servers are created.