Add secilc binary to gitignore

Signed-off-by: Yuli Khodorkovskiy <ykhodorkovskiy@tresys.com>
Set the correct contraint operand flavor for u3

We were overwriting the operand flavor for r3 with u3.

Signed-off-by: Yuli Khodorkovskiy <ykhodorkovskiy@tresys.com>