Update LoRaMac.c

[sbress]

Fixes wrong index in a for loop

[mluis1]

Thanks for the finding. But, I think that the correction would be better as follows:

                //CFList
                if( ( size - 1 ) > 16 )
                {
                    ChannelParams_t param;
                    param.DrRange.Value = ( DR_SF7 << 4 ) | DR_SF12;

                    for( uint8_t i = 3, j = 0; i < ( 5 + 3 ); i++, j += 3 )
                    {
                        param.Frequency = ( LoRaMacPayload[13 + j] | ( LoRaMacPayload[14 + j] << 8 ) | ( LoRaMacPayload[15 + j] << 16 ) ) * 100;
                        LoRaMacSetChannel( i, param );
                    }
                }

Could you please re-submit the patch.