Remove undesired conversions from size_t to int (#1180)

Improve math_brute_force kernels by consistently using size_t to store
the result of get_global_id().

This change was missed in 5d7be40e (Remove undesired conversions from
size_t to int (#1153), 2021-02-11).

Signed-off-by: Marco Antognini <marco.antognini@arm.com>
1 file changed