ANDROID: make virtio_pci_legacy_dev a GKI module

It was removed from GKI modules back in May [1], but that had the side
effect of disabling legacy dev support in virtio_pci.ko [2], which
requires CONFIG_VIRTIO_PCI_LEGACY at the time of building GKI modules.

As a result, after updating prebuilts, virtio_pci.ko no longer depends
on virtio_pci_legacy_dev.ko, and doesn't probe for legacy devices.

This manifested as wifi stopping to work in the goldfish emulator
(b/381881708) - the wlan0 interface was not getting assigned, and no
data was transmitted.

[1] https://android-review.git.corp.google.com/c/kernel/common-modules/virtual-device/+/3081450
[2] https://cs.android.com/android/kernel/common/+/android-mainline:drivers/virtio/virtio_pci_common.h;l=146;drc=97ee04feb682c906a1fa973ebe586fe91567d165



Bug: 381881708
Test: build x86_64 kernel, replace virtio_pci.ko in
Test: kernel/prebuilts/6.6/x86_64/
Test: lunch sdk_phone64_x86_64-trunk_staging-eng && m && emulator
Test: adb shell ifconfig  # notice IP address getting assigned
Change-Id: I7fba4dc9465fbbc6d3f699633706e77b0750b5d7
Signed-off-by: Marcin Radomski <dextero@google.com>