ANDROID: GKI: virtual_device: Add symbols for page_pinner

Add the necessary symbols for page_pinner. Without these,
the build for virtual device will fail with error:

These symbols are missing from the symbol list and are
not available at runtime for unsigned modules:
  __page_pinner_put_page required by ['virtio_net.ko']
  page_pinner_inited required by ['virtio_net.ko']

Bug: 183414571
Bug: 240196534
Change-Id: I00fee050b505cefaa395ad274ba0ee02527a1813
Signed-off-by: Georgi Djakov <quic_c_gdjako@quicinc.com>