add an initial version of WPILib

This is our commit 24ccb7836abaa36b0e913474c818da4b6ae7bc9a which
corresponds with FPGA image v23.

Change-Id: I25b999bbcef39aaea6132562c80360d87780b8c3
diff --git a/aos/externals/allwpilib/ni-libraries/libspi.so b/aos/externals/allwpilib/ni-libraries/libspi.so
new file mode 100644
index 0000000..e77606f
--- /dev/null
+++ b/aos/externals/allwpilib/ni-libraries/libspi.so
@@ -0,0 +1,2 @@
+OUTPUT_FORMAT(elf32-littlearm)
+GROUP ( libspi.so.1 )