Add support for arm64

[brlbil]

Is your feature request related to a problem? Please describe.

This package cannot be built and used on arm64 architecture. Since arm64 started to be used more and more it would be good to add support for it.

Describe the solution you'd like

Add support for arm64 architecture.

Describe alternatives you've considered

No response

Additional context

This is an output from linuxkit metadata package build, which an open PR for adding vmware tools as a metadata service.

GOOS=linux GOARCH=arm64 go build .
# github.com/vmware/vmw-guestinfo/bdoor
vendor/github.com/vmware/vmw-guestinfo/bdoor/bdoor.go:31:10: undefined: BackdoorProto
vendor/github.com/vmware/vmw-guestinfo/bdoor/bdoor.go:33:16: undefined: BackdoorMagic
vendor/github.com/vmware/vmw-guestinfo/bdoor/bdoor.go:35:53: undefined: bdoor_inout
vendor/github.com/vmware/vmw-guestinfo/bdoor/bdoor.go:45:10: undefined: BackdoorProto
vendor/github.com/vmware/vmw-guestinfo/bdoor/bdoor.go:57:10: undefined: BackdoorProto
vendor/github.com/vmware/vmw-guestinfo/bdoor/bdoor.go:59:16: undefined: BackdoorMagic
vendor/github.com/vmware/vmw-guestinfo/bdoor/bdoor.go:61:53: undefined: bdoor_hbout
vendor/github.com/vmware/vmw-guestinfo/bdoor/bdoor.go:71:10: undefined: BackdoorProto
vendor/github.com/vmware/vmw-guestinfo/bdoor/bdoor.go:83:10: undefined: BackdoorProto
vendor/github.com/vmware/vmw-guestinfo/bdoor/bdoor.go:85:16: undefined: BackdoorMagic
vendor/github.com/vmware/vmw-guestinfo/bdoor/bdoor.go:85:16: too many errors