Baudrate error in kl15

[markocont]

Added rounding up and down for calculation of sbr.

/* Calculate baud settings */
float pre_sbr = (float)clockHz/(baudrate * 16); // per arrotondamento
sbr = (uint16_t)((clockHz)/(baudrate * 16));
    if (pre_sbr-sbr>0.5){
        sbr=sbr+1;
    }