Replace the occurrences of signed condition codes where it was
unnecessary by an unsigned test as the unsigned tests allow the full
range of unsigned values to be used without inverting the result with
some large operands.

This reverts commit ee2c909.

Change-Id: Ibaa5e8dfae6ad65bada3cda5f683d181fee37e53
Acked-by: Varun Wadekar <vwadekar@nvidia.com>
Signed-off-by: Douglas Raillard <douglas.raillard@arm.com>