Make v4l2_reader use epoll

It no longer needs to be polled in a loop
and sends images directly to the channel

Signed-off-by: Ravago Jones <ravagojones@gmail.com>
Change-Id: I8fc3efc3fd2cd67836294d9dc47d5342cd7d5de4
diff --git a/frc971/vision/BUILD b/frc971/vision/BUILD
index 159c779..4a8d50b 100644
--- a/frc971/vision/BUILD
+++ b/frc971/vision/BUILD
@@ -28,6 +28,7 @@
     visibility = ["//visibility:public"],
     deps = [
         ":vision_fbs",
+        "//aos/events:epoll",
         "//aos/events:event_loop",
         "//aos/scoped:scoped_fd",
         "@com_github_google_glog//:glog",