Label device-specific android_usb sysfs files.

/sys/class/android_usb/android0/f_mass_storage/lun is a symlink to
/sys/devices/soc/6a00000.ssusb/6a00000.dwc3/gadget/lun0

Label the latter as sysfs_android_usb since fwk is expecting everything
under /sys/class/android_usb to be labeled as such.

Bug: 65643247
Test: sailfish boots with no denial to newly labeled files.
Change-Id: Ib86589facf59234c48ef9e0726277caecbaf16ad
diff --git a/sepolicy/genfs_contexts b/sepolicy/genfs_contexts
index 2ac0d81..0f54958 100644
--- a/sepolicy/genfs_contexts
+++ b/sepolicy/genfs_contexts
@@ -38,6 +38,7 @@
 genfscon sysfs /kernel/boot_adsp/boot                 u:object_r:sysfs_msm_subsys:s0
 genfscon sysfs /kernel/boot_slpi/boot                 u:object_r:sysfs_msm_subsys:s0
 genfscon sysfs /devices/soc/600000.qcom,pcie          u:object_r:sysfs_pcie:s0
+genfscon sysfs /devices/soc/6a00000.ssusb/6a00000.dwc3/gadget/lun0/ u:object_r:sysfs_android_usb:s0
 genfscon sysfs /devices/soc/8c0000.qcom,msm-cam       u:object_r:sysfs_camera:s0
 genfscon sysfs /devices/soc/aa4000.qcom,fd            u:object_r:sysfs_video:s0
 genfscon sysfs /devices/soc/soc:fp_fpc1020            u:object_r:sysfs_fingerprint:s0