During VT-d pass-through, the VMD driver occasionally fails to
enumerate underlying NVMe devices when repetitive reboots are
performed in the guest OS. The issue can be resolved by resetting
VMD root ports for proper enumeration and triggering secondary bus
reset which will also propagate reset through downstream bridges.

Link: https://lore.kernel.org/r/20211116221136.85134-1-nirmal.patel@linux.intel.comSigned-off-by: NNirmal Patel <nirmal.patel@linux.intel.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NJon Derrick <jonathan.derrick@linux.dev>