Fix warning in kernel compilation

[babel] / babel.cl

#include "babel.h"

__kernel
void
fillpage(__global char* restrict page)
{
        /* linearized index in the page */
        size_t gix = get_global_id(0);
        if (gix >= CHARS_PER_PAGE)
                return;

        /* TODO get a character with a specific algorithm */
        size_t cix = gix;
        cix %= SYMBOLS;

        page[gix] = alphabet[cix];

}