[PATCH] NVMe: Create module parameter for shutdown timeout.

[Mayes, Barrett N]

>"Minimum of one second" means "wait at least one second".  It doesn't specify an upper boundary for the maximum time to wait.
>I believe there's a proposal in flight to try and clarify this (or there will be soon).

TP011 for Runtime D3 support added bytes 91:88 to ID controller for runtime D3 entry latency and associated text for host to wait this amount of time to enter shutdown.

A value of 0 still means wait at least one second without an upper limit imposed by the spec.