Don't try to zero-pad the Nexus ID in fpga_test.sh

If the number is already zero padded then printf interprets if as an
octal number, throws an error and prints '00'.  This means tests fail on
nexus08 and nexus09 if you zero pad the number.

Change-Id: I88ea69215a6461df5869d7294a430240665471de
diff --git a/fpga_test.sh b/fpga_test.sh
index f7bc751..abcfe7a 100755
--- a/fpga_test.sh
+++ b/fpga_test.sh
@@ -85,7 +85,7 @@
   usage
 fi
 
-FPGA_BOARD_ID="$(printf '%02d' $1)"
+FPGA_BOARD_ID="${1}"
 ARGS+=(--variable "FPGA_BOARD_ID:${FPGA_BOARD_ID}")
 shift
 TEST_SUITE="$1"