Copy adbd from system/bin to recovery/root/sbin

This change will be submitted with other changes moving adbd from
root/sbin to system/bin. We need to copy it specifically to recovery root.
Previously it was copied by rsync $(TARGET_ROOT_OUT) $(TARGET_RECOVERY_OUT).

Bug: 63910933
Test: normal boot sailfish, checks adb works
Test: recovery boot sailfish, checks adb works
Test: normal boot bullhead, checks adb works
Test: recovery boot bullhead, checks adb works

Change-Id: Ib49605f97a190aec2648cb000d1159b6e15db673