MFC r368632:
Be bug compatible with other operating systems by allowing non-sequential
interface numbering for USB descriptors in userspace. Else certain USB
control requests using the interface number, won't be recognized by the
USB firmware.

Refer to section 9.2.3 in the USB 2.0 specification:
Interfaces are numbered from zero to one less than the number of concurrent interfaces
supported by the configuration.

PR: 251784
Sponsored by: Mellanox Technologies // NVIDIA Networking