cuttlefish: fix qemu /sys/class/net/*/mtu labelling (crosvm version)

Test: via ./out/soong/host/linux-x86/bin/launch_cvd --adb_mode=native_vsock --vm_manager=crosvm

Before:
  $ adb shell ls -Z '/sys/class/net/*/mtu'
  u:object_r:sysfs:s0     /sys/class/net/buried_eth0/mtu
  u:object_r:sysfs_net:s0 /sys/class/net/ip6_vti0/mtu
  u:object_r:sysfs_net:s0 /sys/class/net/ip6tnl0/mtu
  u:object_r:sysfs_net:s0 /sys/class/net/ip_vti0/mtu
  u:object_r:sysfs_net:s0 /sys/class/net/lo/mtu
  u:object_r:sysfs_net:s0 /sys/class/net/rmnet0/mtu
  u:object_r:sysfs_net:s0 /sys/class/net/sit0/mtu
  u:object_r:sysfs:s0     /sys/class/net/wlan0/mtu

After:
  $ adb shell ls -Z '/sys/class/net/*/mtu'
  u:object_r:sysfs_net:s0 /sys/class/net/buried_eth0/mtu
  u:object_r:sysfs_net:s0 /sys/class/net/ip6_vti0/mtu
  u:object_r:sysfs_net:s0 /sys/class/net/ip6tnl0/mtu
  u:object_r:sysfs_net:s0 /sys/class/net/ip_vti0/mtu
  u:object_r:sysfs_net:s0 /sys/class/net/lo/mtu
  u:object_r:sysfs_net:s0 /sys/class/net/rmnet0/mtu
  u:object_r:sysfs_net:s0 /sys/class/net/sit0/mtu
  u:object_r:sysfs_net:s0 /sys/class/net/wlan0/mtu

Bug: 131863575
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I93745f6311884d597b4531f477633f6b18548ab3
Merged-In: I93745f6311884d597b4531f477633f6b18548ab3
(cherry picked from commit 53651ba41e59d57921186a1e98ed90ddac486f72)