Preallocate dma edge counter array

We can only ever have 4 edge counters due to hardware limits, so let's
just use a sized array.

Change-Id: I07fe7c27b64f2c0878cdc9844dbd304fa7f94d48
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/frc971/wpilib/BUILD b/frc971/wpilib/BUILD
index 10e8462..049efae 100644
--- a/frc971/wpilib/BUILD
+++ b/frc971/wpilib/BUILD
@@ -42,6 +42,7 @@
     target_compatible_with = ["//tools/platforms/hardware:roborio"],
     deps = [
         ":dma",
+        "//aos/containers:sized_array",
         "//aos/logging",
         "//third_party:wpilib",
     ],