Drivers: hv: vmbus: Introduce hv_get_vmbus_root_device()

Drivers: hv: vmbus: Introduce hv_get_vmbus_root_device()

The ARM64 PCI code for hyperv needs to know the VMBus root
device, and it is private.

Provide a function that returns it. Rename it from "hv_dev"
as "hv_dev" as a symbol is very overloaded. No functional
changes.

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/20250428210742.435282-10-romank@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <20250428210742.435282-10-romank@linux.microsoft.com>